No you can not.

can i run in seperate conduit

can not run UF at all. Pool wiring prohibits uninsulated ground wires. THWN conductors would have to be ran in conduit

If you don't know that, there are a lot of other pool requirements that you don't know either. Get a professional to wire a pool. This is no place to practice electricution (sorry Freudian slip) when you haven't even read the code requirements. Pools just aren't a do it yourself project. Mistakes around water and electricity and you, or heaven forbid someone else, may never get out of the pool. If you can't afford to hire a pro, you can't afford a pool.

yeah, I agree. That's why I won't touch my dead pool light. I have a pool service that handles all electric issues with my pool equipment. These guys find things I'd never think to re-do or upgrade. Worth the $$ everytime.

I am installing a new 220 vac pump. I am using a 220 gfi breaker in the subpanel. At the pump I will be using a knife switch. Should the switch be fusible?

Thanks

No you just have to put a disconnect within sight of the equipment (or provide a provision to lock it). There's no requirement to fuse it unless the pump instructions (unlikely) require such.