Can you look at this train schedule please?

You are concerned about transfers, which is understandable. In your shoes, (and with the understanding that fewer transfers with bags is better than more transfers!) I'd break up the trip looking for journeys as follows at the sites you are using. Only the Paris > Strasbourg leg will need to be pre-purchased.

Aug 3:
1) Paris > Strasbourg (direct, pre-purchase tickets)
2) 1 Transfer to local train for Strasbourg > Offenburg (Special day ticket, "Europass 24h Family"... 16.60 for all of you, no pre-purchase... just buy at Strasbourg station.)

https://www.ortenaulinie.de/,Lde/startseite/fahrkarten/europass.html (choose "en" for English.)

Spend the night in Offenburg.

Aug 4:

With your bags in Offenburg, you can now travel to Europapark without them.

Train to Ringsheim + bus to the park as previously planned This trip takes 30-35 minutes (8:36 - 9:07 for example.) You can travel round trip from and back to Offenburg on a day pass called the "Baden-Württemberg ticket" if traveling after 9 am, OR at any hour on two one-way tickets (BW-Einfach fare.) Buy these using the DB app or buy at the station; both train and bus are covered with either option. Either way, your round trip fare will be somewhere around €40, depending on the ages of kids (under 15 travel free with parents.)

Spend the night in Offenburg again.

Offenburg is a rail hub town with the basic services travelers need and and a nice enough place for overnight.

Thanks for the reply Russ. We do have accommodations and park tickets booked already on site at Europa Park so stopping over in Offenburg won't be an option. For the family day ticket you linked, is that valid for our travel from Strasbourg all the way to Europa Park, including regional trains and local bus we'll need? I saw a pass on the dbregiobus website but I didn't realize it is valid for the trains as well? That would be a great deal if that is the case.

ETA: I'm not seeing the option for the 24 hour Europass anywhere in the DB Navigator app. I'm looking at routes from Strasbourg to Ringsheim/Europa Park and have also checked Strasbourg to Rust and I don't see it in any of the offers. I've checked for tomorrow (since it has to be purchased 24 hours in advance) as well as a few other dates. What am I missing?

Trainline should show the same trains as Bahn, and the train you assume to be "Grand Vitesse" is the TGV. That is what the G and V in TGV stand for :-)

But if Trainline is cheaper (maybe because they dip in the SNCF fare buckets and not the Bahn fare buckets) by all means buy it there. Transferring in 4 minutes is perfectly feasible. But if you miss your connection you just get on the next one...

"I'm not seeing the option for the 24 hour Europass anywhere in the DB Navigator app."

No worries.

This pass is offered by TGO, the local transport authority in Germany, and by CTS, the local authority in Strasbourg that cooperates with TGO on this special ticket.... and sometimes these local options do not show up on the DB app. This ticket does NOT need to be purchased 24 hours in advance; it is valid for 24 hours beginning at the time of purchase and can be bought at the last minute in Strasbourg (or in one of the TGO towns in Germany, like Offenburg, for anyone going the other direction.)

Here is the CTS site which offers the Europass on the Strasbourg end of this cross-border journey...
https://www.cts-strasbourg.eu/en/buy/our-tickets/occasional-tickets/europass-mini-24h/

TGO/CTS tickets will not cover you all the way to Ringsheim, which lies outside the TGO zone. So, with a pre-purchased ticket for Paris > Strasbourg, you would add on as follows:

• TGO 24 h Europass Family "MINI" (€12.80) - covers Strasbourg > Kehl (border town in Germany) on any regional train.

• Then either the a) BW Einfach ticket (one way to Ringsheim) or the b) Baden-Württemberg ticket for the Kehl > Ringsheim > Europapark segment by train + bus.

With a) you must buy the ticket from Kehl all the way to Europapark in order to include the final bus trip from Ringsheim.
With b) every inch of your travel from Kehl onward is covered.

When you travel Strasbourg > Ringsheim on the first ticket, the train will travel to Kehl and continue after a stop there to Offenburg (where you change.) Your Europass ticket ends in Kehl, but you stay on the train in Kehl - which means that in order to have a valid ticket for the Kehl > Offenburg segment, you will need to have purchased the 2nd add-on ticket from DB on your phone and have it available for viewing prior to the train's departure from Kehl.

I am not checking all the possible fares from Paris to Europapark at all the different sites for you, which I think you have already done... I'm just informing you of these relatively cheap add-on tickets that can be used for the regional trains and buses you will need from Strasbourg onward.

Hope I hit all your concerns here. If not, re-post!

just a little more about the name of the train from Paris.

It is the high speed train in France - the name describes what it does. TGV is "Train à Grande Vitesse" in French, it literally means Train of High Speed. The speed is indeed high - up to 320 km/h.