As others have said, you can definitely do it all, especially if you have a base in Paris city centre and are just planning to visit
Disneyland for one day (using the RER train from central Paris which takes around 45 minutes each way).
The comments above on the Eurostar are mostly about a Eurostar from Disneyland, which as others have pointed out is limited. But you've said you're leaving Friday: in that case I'd recommend spending a different day in Disneyland (Tues, Wed or Thurs) as crowds will be much lower.
Your last day (Friday) being in Paris, you would get the Eurostar from Gare du Nord in Paris to London. It is cheaper and frequent, with trains running quite late. It is in the North of Paris, not too far from the Sacre Coeur, so offers a chance to see that before you head off on your train. Going up to the Sacre Coeur and looking out over Paris at sunset is one of my favourite things to do in the city.
While I am sure you can fit everything in, try not to stress too much about ticking things off the list. Living in Scotland, I'm lucky to be able to visit Paris often but I would strongly suggest taking time to just wander, soaking in the beautiful streets, strolling by the river, stopping for a glass of wine and watching people....it can be a very relaxing city when experienced this way!
Regarding doing Disney in one day: I'd suggest spending a couple of hours in the Studios first to experience the rides that you don't have in the US, if this is important to you, then spending most of the day in the beautiful Disneyland Parc. The Studios has some fun attractions but it is a small park which sadly doesn't have much going for it looks-wise (yet!). The main park is stunning, huge and deserves lots of time to be seen properly for big Disney fans