Requesting advice for my first saltwater tank: FOWLR 10g...on a budget.

Hello!

I am starting a budget saltwater fish-only (FOWLR) tank. My first SW! I plan to use a Fluval C2 HOB filter (119 gph) and a 10g tank, both of which I have lying around. I have a few questions but haven't been able to find info online. (Most sites stay kosher with required equipment, and meanwhile I am trying to see what I can reasonably get away with not having.)

(1) How important is it for me to have a small powerhead for circulation?

(2) How important is it to have a separate bucket (with a heater and powerhead) for mixing salt with water? Some say I need both and to wait 24 hours for the salt to dissolve/circulate in the bucket. Others say simply mix and then on to your water change!