Summer Elise -HP / +DEF and Reinhardt -HP / +SPD

I mean they aren't the worst. Reinhardt in particular only has one relevant stat...which is attack. Unless you have -atk, he is pretty usable.

For Elise, her boon isn't that useful but her bane isn't crippling. Use her for now if you like her, but +spd/+atk is where she'd shine.

So if you want to use them now, do. But you could also wait for better IVs. Reinhardt doesn't require too much investment so of the two of them he'll be easier to utilize.

If you don't have a Nino and want to build Elise as a pseudo one, that's fine. I would probably just wait on summoning an optimal Nino and build her; but that's just me.

Reinhardt is 100% worth building with any bane that isn't attack. He may not be optimal; but he'll still wreck shop. You can always merge him into an optimal one if you pull one later.