Keep or Reroll?

Re-roll

I suggest to reroll. If you dont have anythig other than those 2, Ayra is still great with - spd but try to get at least neutrall atk and spd.
As for Zelgius i cant say anythig, since i never had him.

Welcome back and I'd say reroll if you have patience to spare; you can do better than that. Big Z's not hopeless with that IV by any chance but it's still not desirable. And Ayra would definitely enjoy different IVs.

Also it might be easier to charge back into fray if your 5* units would be different colours.

Reroll, Ayra definately wants to have as much Spd as possible due to her special. Your Zelgius could be more of an enemy phase physical tank with lower Atk, but he’s not completely awful, a -Atk +Res would’ve been worse, a lot worse.

If you have the patience, then I’d say reroll. Other than that, the two are workable, though not optimally beneficial... For example, Ayra can really use any point of speed she can muster while Zelgius is rather okay.

Wait a few hours for Legendary Banner and re-roll then

Don't reroll, those units are fine, if you get others you can merge them for better iv later. If you got Ayra and Zelg on 40 orbs, that's about as good as it gets....

Aside from colorless, this upcoming legendary banner isn't even that good.