welcome to this forum!
It's good that you skated as a kid, I wish I had. You never learn like a kid any more, but the fun in roller skating never stops.
: Could you guys suggest skates for a beginner who is going to (eventually) try both derby and vert skating?
It's OK to try stuff with some pair of skates. But there is no such thing as a pair of skated suitable to everything. Back in the times (TM), I tried to have a pair of skates equally well suited for cruising the streets and for riding half pipes. It turned out that they weren't really good for neither. Now I have a pair for cruising and a pair for ramp riding. It's OK to misuse them outside of their purpose occasionally, but it doesn't really work.
Therefore my advice would be: Get a pair for ramp skating (it's best to build them yourself or have them built) if that's what you're up to. It's OK to try your first moves on any skates but you soon will want to move to more suitable skates as you progress.