Well, I of course do not know what you have found in the meantime (I'm a little bit late to the party as sometimes...) but just a few remarks:
1) I have no clue who is the quoted Forex Broker, however if they do not like countries like Seychelles and BVI, I doubt they will like Cayman Islands.
2) To get “a decent corporate bank” for a newly established company at Cayman Islands is next to impossible. Nowadays.
3) I agree that a company formation is generally worthwhile (in a reasonable jurisdiction).
4) If she eventually wants “to open up investment services to friends/family”, it's highly recommendable not to mention it anywhere (including here perhaps with the exception of Mentor︀ Group). (I presume she has no intention to do it formally, i.e. to get an︁ appropriate licence/s/, establish KYC/AML/XXX teams, etc. etc.) It means, that the words “or more” should︂ be totally forgotten 😉