Have to agree with Lechen being stronger then a fair wack of the gatcha girls.
But then the girls have never been balanced to be honest.
Toad Lilly is basically a 6* without the full atk, her defensive stats are actually higher then most 6*s right now.

As for getting flower gems... for FTP peeps they do come fairly often, about enough to do a 50 pull every 4-5 weeks.
That in itself is not terrible considering the price if you buy them.