>>530292714
Okay... It's unlikely to get the girl you like because the 3* pool is pretty big now, but a lot of them are farmeable at this point. Or you can buy the selector if you REALLY want her.
1* means she is welfare, her event is in fact archived so you can claim her from the start, just reading the first chapter of summer Gehenna.
Some alts are better than the base version, it depends. Meta is not that important in this game, I take my wife to pvp every day and still get plat.
The only case where newer girls were needed to complete were content were specific raids that used specific mechanics, it's not a big deal and if I don't have the girls I just skip it.
Once you get to the end this game takes like 20 minutes to do dailies, it's only grindy early on when you have to manually clear stages.