Depends on your date I guess but these trains sell out days in advance in summer so my answer would be a definite no.

If you land in the morning simply book an afternoon train and there's 99% chance you make it. It's only 18€ pp I mean and guarantees you a seat.

If you don't want to go to Paris city center (RER B is not included, 12€ ticket) you could take a TGV straight from the airport to Strasbourg.

EDIT : I had a look at your post history so you're looking for Saturday 13th April, right? All trains have at least 10 seats left but they could fill up. Don't chance it and book an afternoon train to Mannheim (18€).

I did some research and it. Seems I should only add in the. Legs that need a reservation. Yes my travel date would be 4/13. I decided to go to Zurich instead. I am scheduled to land at 10.30 and would go to gare est. Not sure if attempting the 12.55 to Strasbourg is too aggressive. The reservation fee is 20e pp. 

When I typed in cdg rossy T1 no trains were provided. How do I find this train. I been keying in 'Paris '

I went to the raileurope site for a routing directly from CDG to Strasbourg and it found me trains from the airport for 11.22 which is not realistic.  

There was an additional train at 12.01. This has a higher seat reservation fee w a connection.

I do have the option of taking the 12.55 train from paris est if I leave by 12.

For my back up, there's a train from the same station w connections to Zurich leaving at 13.51 where as options are surprisingly limited from CDG. 

The reservation says I could change it once with out penalty 30min prior to after train departure. My question would be could I change my ticket from cdg airport to the gare est? 

How do I go about exchanging my reservation? If I miss my 12.55 from gare est, there are direct trains from gare Lyon. Can I exchange it from gare est or gare nord for my train at gare Lyon? Can I exchange it via the app or does it need to be a manned ticket office or a machine? I googled and find no instructions or publications anywhere. See attached of the terms and conditions. How do I pay for the upgrade fee? Or can I only exchange it for a later gare est Strasbourg train? 

There is a chance I might need to do it at gare nord if can't be done in the app as it is the most convenient stop on the rer b line. 

You're showing the B-Europe website in your last screenshot. As far I know, exchanging pass reservations is only possible by phone, which is not really convenient.

I'd use the Rail Europe website. Book a train of which you're 99% certain you'll be able to reach it and if you get to the station early enough for an earlier train, then first book a new reservation and then cancel the old (later) one.

What’s the benefit to using the Rail europe site? i been using them to find possible trains.

When I reached out to eurail, they mentioned how they can allow me to cancel the ticket within the app? they also said regardless of what i use for the reservation I’d be able to cancel at the station?

Per the terms and condition, it seems like I can only cancel/exchange up to 30min before and after the train leaves.

My safe bet is the direct one from Gare Lyon. it is slightly more expensive.The one I’d like to book is the one from Gare est that leaves at 12.55.

I tried calling SCNF, man got a super rude agent telling me to contact interail. telling me they dont allow changes after departure of the train.

It's cheaper since they don't have additional booking fees. Eurail and B-Europe do have those.

In addition, you should be able to cancel or exchange reservations yourself from your Rail Europe account. I haven't used that yet myself though.

The rail planner app can't book any reservations and consequently can't cancel them.

You can only cancel or exchange reservations through the provider you booked them with.

Up to 30 minutes after departure time.

Although it's unlikely they have different conditions than Rail Europe or B-Europe, I can't say for sure because SNCF don't publish their conditions for refunds and exchanges of pass reservations.

Thank you very much for the details.
For some reason during my prior searched b-europe came to be cheaper Seems like they are the same when i’m using my computer. I’m attaching the screenshots from both sites and both contain the same language on the terms and condition for the exchange. Being able to cancel and exchange in an app would be much convenient. I do wonder if they really mean free of charge without any penalties. I would want to try for the 12.55 and switch to the 14.21 direct if I miss it but need confirmation that it can easily be cancelled without penalty. Assuming there’s room obviously.

The scnf lady said i could change the ticket from CDG TVG station for a later train at Lyon or ESt but then I’d be at CDG outside of the allowed 30min before and after time criteria

Where can i find reference material for this? I couldn't find any online. How come bloggers don't even discuss this.

Rail Europe has an app but I don't know what you can do with it. In any case it can't book pass reservations.

Like I wrote, I'd book the later train in any case and cancel it if not needed. You could also book the earlier train but then you'd need to make sure you are able to cancel in time if needed. After booking the later train, go and check where and how you can cancel. I'd think it should be working with a web browser in any case.

You could always consider changing your flight to one that lands where you want to be . . . and then start your train travels from there.

Realistically, if I was landing somewhere as large/busy as CDG at 1030 and had to pick up bags and go through immigration I wouldn’t plan on being land-side with my luggage until after 1200.  Anything earlier would be a bonus, but I wouldn’t plan my travels around it.  I wouldn’t plan on being in Paris (Gare de l’Est or Gare du Nord) before 1245.  And getting to Gare de Lyon - 1330.  You may be lucky.  You may be unlucky.

As per rvdborgt above - book what you think is achievable, allow time for unexpected delays getting through an airport the size of CDG and getting across a city the size of Paris, include time for something to eat, value your stress-free time more than the €20 for the reservation, arrive in Zurich fresh and ready to face paying €7 for a coffee.

Thank you for the responses. I'll keep my eyes on availability and probably book it before my flight leaves. 

Changing my flight unfortunately is not an option as it's prohibitely expensive.I am currently leaning towards just booking the direct 14.41 train from Lyon. Try canceling to see if it is really free prior to departure. If clear immigration/customs on time and get to terminal 2 before 11.45, I would buy the 12.55. I don't plan on checking bags so if the flight is on time then I should be able to make it and obviously assuming it still has seats for reservations. 

Note that the TGV to Basel/Zurich from Gare de Lyon leaves at 14:21 and not 14:41.

Right now either train has over 20 seats left so it should be fine.

But don't you want to have lunch somewhere in Paris, be less stressed overall and then take the 14:21 train?

Yes 14.21. thanks for correcting me.that was a typo.

I made the reservation and can confirm I can cancel within the app. Up to 30min after departure.

Could I pay to reserve the earlier train as well?  Then cancel whichever I don't make? 

How do you know both trains have over 20 seats? 

I will have 2 carry on suitcases along w a back pack and a kid. Don't want to go anywhere but near the train station for a meal. If I don't have time. I'll buy on board. Will be tired from the 10+hr flight 

Yes you can book a second train : reservations are totally separate to the app/pass.

I've had a look on SNCF (like if I were to buy tickets) and there's no notice such as "x tickets left". I've also counted seats left using the seat map (only available in 1st class).

That doesn't mean they won't fill up in the next 10 days of course.

Yes of course I meant a meal in or near the train station. That way you will be less stressed. It's up to you.

Thank you all for the assistance 

I was able to get on the 12.55 inoui train. It is pretty much the same type of train that I took when I went to Antwerp. Pretty crappy train, no premium feeling at all. Would def upgrade to first class next time.