According my knowledge the Eurail/Interrail pass is not valid for Eurostar services to Marne la Vallee You have to catch a train to Lille (change to a domestic TGV to Marne la Vallee) or catch the eurostar to Paris and then use the RER System of Paris to get to Marne la Vallee :) 

Hey! Perfect, thanks for the tip. This TGV that you mentioned it, it’s available for Eurail Global Pass, is that right? It’s my first time to Europe/UK tks!

Yes the TGV accept Eurail but need a reservation too :/
I suggest to check what is finally cheaper

Eurostar to Lille + TGV to Disney (usually 10€ or 20€ reservation on top of Eurailpass)
or Eurostar to Paris + ticket for RER System to Disneyland (the RER train to Disney is not covered by Eurail )

Wow, thanks indeed! I’ll search for this. Another qq: here in Rail Planner I see some options from Paris > London. Which one is the closest to Disney? Can you confirm pls? (Attached) 

@Ana Talavera  From London there is only one station served in Paris (arrival of Eurostar) it´s Paris Gare du Nord :)

From Paris Gare du Nord you have to find your way to Marne la Vallee (this is the closet station to Disney) as mentioned above with Public Transport of Paris :)
The RER (something like Metro) Line A serve Marne la Vallee but note that the RER to Marne la Vallee is not included any you have to pay extra :)

Thanks ;-)