Which girls are good for pvp after all the updates and where is recommended to farm them and their weapon? I'm f2p newbie.

Water: Naladia (Advanced Exploration | Noble Shop: Is 10k coins worth it for 1 shard? | Arena Store: Is 150 Merit worth for 3 shards of weapon? | I heard there are shards for her on Arena Store but I haven't seen them. If I find them, should I buy them there?)
Fire: Elnora (Advanced Exploration | Noble Shop: Is 120 diamonds worth it for 3 shards as f2p player? |
Earth: Chharodi right?
Wind: ???

I know I need to farm them in Advanced Exploration but I'm not sure if 10k coins is worth for 1 shard and 120 diamonds for 3 shards (as f2p player) in Noble Shop, 150 merit for 3 shards of weapon and 160 merit for 3 shards in Arena Store, 160 trials for 3 shards in Trial Shop, 160 League Coin for 3 shards in League Shop because someone mentioned that it isn't worth it to spend arena coins on 1* girls.

Also which bonus stats (if atk isn't available) should i look for?

For physical girls:
Helm: Cri???
Chest: P. Atk
Gloves: P. Atk
Pants: Cri???
Boots: P. Atk
Ring: Acc or M. Def???

For magical girls:
Helm: M. Atk
Chest: Cri???
Gloves: M. Atk
Pants: Cri???
Boots: Acc or HP???
Ring: M. Atk