my 2 cents,
1- you are correct for pre med the loan doesnt cover all, if there are other loans I don't know that one. call the financial affair office they will tell you all there is to know.
2- for the clinicals you have to speak spanish b/c the population of the country speaks spanish, few people will speak english.
Look at it this way speaking spanish will save you a lot of headaches.
3-Residency is possible once you pass the usmle's step 1/2ck/2cs and get ecfmg certified. Most programs are looking for applicants with US clinical experience so it would help to do an away rotation.
4-Housing depends If you want very near school, nice place then it will be expensive like around 750/1000+ per month. here is where the spanish or dominicans friends comes in handy for that price to come down.
Not close to school then the price really goes down.

I suggest you come down and check it out for yourself talk with a few people in the courtyard of the university, usually AM since the basic science people tend to have class in the mornings. I suggest Hotel Lina as the hotel is in the same block as the university.
GL