ignoring all the fluff so far in the thread. www.velocityfutures.com will probably be able to help with your spec, except the 1:100 leverage bit. if your mates want to day-trade with high-leverage, some FCMs allow day-trades with margin as low as $300 for ES/YM/NQ. velocity offers them for $500/contract. i don't see any issues opening accounts with any FCMs as long as W8BENs etc are filled out, and identity can be verified.
foreign accounts suck for most firms...you have to jump through sooooo many hoops and if you miss one...THUMP!! 5k firm from FINRA for Violating AML and Patriot act rules...not worth it to many firms and clearing houses...so instead they only take on the large foreign institutional acounts.