No, a HUD is not mandatory. I dont use one. And yes, you need to be playing at least 25NL at PS to get anything from the VPP program. All sites are full of fishes at 5NL, dont worry about that.

You will need a HUD though if you insist on playing a ridiculous amount of tables. I think you should start with no more than 4 and no HUD. Take notes and make good reads. Learn about ranges, flop texture, equity, EV and everything. The sooner the better.

GL