Do crystals attached to a weapon survive going to the wardrobe or being lent to another player?

Nope. If you remove a weapon from your armory you lose the mod crystals attached.

Now I'm a little sadder about how the changes will affect being able to get some duplicates, but I'll survive. But dang, I should have given Natasha a little time to shine on an HA before putting it in my armory.