Good suggestions. And i really like Scotch Broom (I have her on Nutaku).
My biggest problem with SB-Teams is the restrictive Team Building:
-Only Rainbows
-To maximize such a team you basically have to include Girls with the 50 % Light Gauge Ability (to reach the 300% cap) even though they are no Solar Blast Girls.
In Mei's case that's not a problem cause i already use her in my Crit Squad. I don't have any free spot for Cattleya though.
She would weaken my Crit Team, Debuff Team or Counter Team (cause she has no Synergy in any of these teams) just to strenghten my Solar Blast Team.
To optimize SB you have to invest a lot. It's so strong though. Ardisia Bride i would have to wait 4-5 months to promote her. I don't have any shards atm