Hey,

The Doors close 2 mins before the departure and you have to pass through automatic gates at the platform in Paris. So I would recommend to be there at least 15 mins in advance.

The change in Basel SBB is quite short. You are arriving at Basel SNCF and have to walk through the main station building and then go up the passerelle to get to the platform for the IC. 8 mins is usually not a Problem but with a slight delay it might be. The train won’t wait for the coinnecting passengers. I recommend you to board the train from Mulhouse to Basel at the very front. Then your way will be shorter. Also keep in mind that you are crossing a border - there are sometimes custom controls on the platform in Basel SNCF but they just pick a few people…

The change in Visp is straightforward. It is not a big station. 

You already arrive in Mulhouse at 15:03, so you could also take an earlier TER to Basel at 15:19.

As advised take the direct TER from Mulhouse at 15:46 (and not 15:49). It arrives in Basel at 16:08. The 15:19 train from rvdborgt doesn't seem to run on weekdays.

In Basel I much prefer 20 min than 8 min

Then Visp is a guaranteed connection and lots of people will do it

There’s no 15:46 option on Rail Planner though.

If I miss the connecting train from Mulhouse, Basel, Visp (which seems quite likely) can I just board the next one? 
 

Yea, you can just board the next one. In Switzerland you don’t need any reservations (except for some special panorama trains) 

The 15:46 train is on the app. Search between Mulhouse and Basel SBB only and you'll see it.

Yes the next one will be 30 min later (as most trains in Switzerland). Simply add it to the app before boarding and hop on.

Thx everyone for the advice