Ace, 6P is a high mid. In these situations, I use 6K instead and it's effective to mix 6P with 6K. If you have more advantage or as an [abare], you should try 33P.
But with these moves, it is also possible to bait and punish as they are unsafe, like Marie's 3H+K (punish with low throw).
Not glitches, check out muh explanation for Helena's Bokuho duck which also applies to other moves http://www.freestepdodge.com/threads/details-of-the-bokuho-stance-duck.6515/
Dont you know the rule of DOA5? if it looks like a crush, it IS a crush, which is one of the more annoying things in this game. real talk though that last one with mai, her 4p is one of those moves that pulls her hurtbox back really quickly so it can used in minus situations to avoid short range mids, Gen fu has a similar thing with his 4p+k