Best way of getting new skins?

[LadridiCardos]

So this. Are there some things that I need to know to get the more for free/grinding? should I gacha using the diamonds or do I use it to buy Season pass? (If that's even possible) do Farlight store items change through time? At the moment is the fastest way I unlock some Maychelles without using all coins.
Also, not related. Do you have these bugs playing Phantom?
-People seeing me when using "Phantom trick" (not by getting caught by any abilities like Maychelle's Sonic tracking). -Doesn't happen all the time, but it happens a lot-
-Having a long delay to shot after using "Phantom trick". The necessary seconds for the enemy to see me and beat the ♥♥♥♥ out of me.