I have the exact same set and I treat it as a general exploration gear. Or a tanking set kinda. The Wolver set line gives health bonuses while the Owlite set gives elemental resistances, so if you just want something to give you survivability, I think it works. Although depending on your playstyle (if you want to be a swordsman, bomber, gunner, want high damage, want to resist specific elements, etc) it helps to look up in the wiki and see what bonuses the different sets can net you, and be able to invest your money and energy into upgrading those.

I think that at first, in order to experiment with weapons, carrying around sword + gun or sword + bomb is nice... then, when you'll really know what you like, you can carry 4 swords if that's what you're into ;)

I have grey owlite and VPS so it depends on what run your doing. You should actually get both.

Unless you plan on doing lots of jelly runs. In that case, get a shadowtech. Add me: IGN Bigfootm

Re: Your Alchemer:

Actually, especially if you plan on doing lots of JK runs, anything but Shadowtech. You plan on making a Nightblade, so you'll have a shadow damage sword. Having a second weapon that deals the same damage type is both redundant and potentially dangerous. You're going to meet enemies that are resistant to shadow damage, having one of the elemental Alchemers is good sense. Particularly in the Jelly Palace, where in addition to Jellies you'll also meet Constructs (Gunpuppies and Lumbers) which are weak to elemental, and Fiends (Silkwings) which resist shadow.

As for which one: I like the Cryotech, but the Voltech is also a good option, as the status it inflicts can co-exist with people using Firey bombs, and isn't redundant if someone else is carrying a Shivermist or something. Just don't get the Prismatech. It doesn't inflict any status, and doesn't deal any more damage than the ones that do.