As a quick note, this thread is from 5 months ago and the OP has transitioned into a better credit profile (NFCU for starters).
CreditOne and FP do serve a purpose, for some they're almost mandatory but for others there may be better options. It all depends on one's individual credit and finances as to whether they're a good fit for any individual.
I'd agree with the sentiment that 1 card simply prolongs the process of rebuilding, and that 2 absolutely better 1, and 3 perhaps slightly better than that. That last part (two vs three cards) is hard to quantify though on paper for aggregate payment history and getting out of thin-file status, three cards is worthwhile especially if the rest of one's positive history is slim.
Starting Score: EQ 5 561, TU 98 567, EX 2 599 (12/30/11) Current Score: EQ 5 771, TU 4 758, EX 2 758, EQ 8 795, TU 8 762, EX 8 786 (7/28/17) Goal Score: EQ 5 750, TU 4 750, EX 2 750, EQ 8 800, TU 8 Blah, EX 8 800 (01/01/18)