Tom, that is one heck of a journey. You should certainly see a good selection of trains on your travels.
I am not an expert on night trains in Europe but a quick look through the timetables and websites on the internet reveals the following details. Your "Elipsos" journeys from Paris-Barcelona and Barcelona-Milan will be in Talgo trains. These are high quality hotel trains consisting of rather strange dumpy coaches which share the same single axle truck. "Elipsos" have a website
here
Your daytime Milan-Zurich journey is over the scenic Swiss Gotthard line and will be an Italian/Swiss "Cisalpino" tilting electric unit (
like this one) "Cisalpino", the operating company have a website
here
Your night journey from Zurich-Vienna is on the EuroNight "Wiener Walzer" which as far as I know uses OBB Austrian Railways standard sleeping cars. Motive power from Zurich to the Swiss/Austrian border will be a Swiss SBB Re4/4 ll electric loco (
like this one). An Austrian electric loco will take over at the border for the rest of the journey through to Vienna.
I don't know anything at all about the Vienna-Prague-Warsaw-Berlin part of your journey but I suppose this could be your only chance of diesel haulage but even then I doubt it.
You will return from Berlin-Basel on a "CityNightLine" service. This is another high class service and some of their sleepers are actually double deckers. "CityNightLine" have a website
here Loco will be a German DB electric.
Your Basel-Geneva daytime journey is on a Swiss SBB ICN tilting electric unit (
like this one) and the leg from Geneva-Paris is on a French SNCF TGV high speed train.
As you can see most of the motive power is guaranteed to be electric so there will be more sparks than thrash
Hope this helps,
John.