[1]

It should be ok to show the PDF on your smartphone. No conductor in Italy did care about this on my last journey. 

>2]

Just a tip for next time: It's possible to see the allocated seats before doing the payment. So there's no need to take seats you don't want. They can't be changed later. It's just possible to cancel the supplement. The only way would be to do a new reservation without supplement. 

To give adequate advice for the 1st question: Which dates and time do you plan to take this train? You managed to reserve them eventually or not?

For the second question, yeah if the seat allocation is random. Just ask your fellow passengers. Half of the time I reserve seats, when travelling per two, I end up not sitting on the reserved seats, but just agree to switch some seats with fellow passengers so that some people can sit together. It happens often and no need to worry about that.

Well, happy travels! I am sure it will go along just fine-with the odd minor and most easy+fast to solve little prob.

@1. surprises me, but as you do not mention any date nor data I suspect it could be works along the way-OR the need to change and partly use a traintype that is out of scope for RES.

As one cannot fly into Vre anyway: I conclude you must be in IT a few days before-on travel-so just pop into a TrenIT counter- as seniors (like me) you should remember that was/and still is a very common way to get it organised. Noone forces you to put it all on the fone! Same price as OeBB-3€ for any IC ride (2nd cl.) And on any day there are multiple options, so a tiny little bit of flexibility always comes in handy. Or is there maybe something with a famous Carnival in Viare?

@2. THESE direct trains IT-AT-DE ALL have a surcharge for passes of 10€-and as such there is NO mandatory RES-if ´system´ points such for you faraway places, then most likely that day there are already so many bookings it could not find any better.  As these trains are out of scope for TrenIt (that is why that supplt is there-years ago TrenIt simply stopped doing any INTernat. trips-their counter will not able to help- there MAY be (there is at least one in Verona and Bolzano) a special OeBB/EC counter that may help.

The seat options were aisle, window, with table. I never saw an actual seating plan.

We'll try and do a seat swap  as suggested.

Surely oebb could tweak their app software to have  more customer friendly sear selection

Yes we are going from London to Nice first then making our way to Viareggio for the Carnival.  

We leave Viareggio on 17th Feb, national rail strike day.   The train to Salerno is listed as an Essential Service according to Trenitalia website.

You didn't say which train but I found 1 direct day train. Reservations are available via ÖBB:

Yes, that's the train we've booked. The tickets are not available as a mobile ticket, as expected, the app flags this up, only as an emailed pdf.  

Perhaps this is because it is a strike day essential service.

Or does it apply to all domestic Italian trains booked on oebb app?

If you experiment with the ÖBB app you can get to a seating plan and choose the seats you want, this is before you pay.  Just done it for Venice to Villach. Once done it can’t be changed. The pdf is fine in Italy you’ll only need to access it if someone is in your seat. The conductor normally won’t need it as all the info is on their iPad.

That doesn't work though for domestic trains in Italy.

Thanks I didn’t know that!

You are understandably confusing tickets with reservations. When you buy reservations from OEBB you are buying a “ticket with reservation” with a 100% discount on the travel cost. Therefore the pdf, which would normally be a paid for ticket, is now a reservation which has to be supported by a validated pass (i.e. “proof of payment” of a valid ticket.

If you were to buy a ticket you would get an identical document in pdf format but obviously without the requirement to show any further evidence of payment. 

My experience of Italian trains requiring reservation was they always needed to see the OEBB or Eurail pdf “ticket” with your seat number and then may or may not check your pass, but showing only your pass was a no-no as it didn’t show the reservation had been paid for.

I've done some practice bookings, stopping before payment, in oebb.

Innsbruck to Chur, yes seat choice available on RJX.

Venice to Villach, yes seat choice available on RJ

Venice to Innsbruck, no seat choice available on EC.

So EuroCity is the problem

A seat plan on oebb.at is only available for RJ and RJX trains. All other trains have not this option. Deutsche Bahn should be able to do that, but at an additional cost.

In Venice they can't change that, because the Eurocity is operated in Italy by DB and ÖBB. In any case you have to ask directly where you have booked for this questions.

In your case the best solution would be to ask ÖBB via Social Media direct messages if it would be possible. Normaly should be not possible, because optional seat reservations on trains are not refundable. 

Our Italian travels went well, very impressed with Trenitalia for punctuality and cleanliness.

We followed the advice  above and booked all our subsequent Italian reservations in person at a station..... it happened to be Salerno where the girl spoke excellent English.  Thank you from one senior to another, mcadv!

One reservations was from Reggio di Calabria to Bari via Taranto.  Although Reggio to Taranto is an Intercity train, all seats are 2nd class ( we have 1st class pass)