Vegeta, Gohan, Krillin vs 1st Form Freeza

If Freeza didn't transform, could they defeat him without Piccolo and Goku?

I guess how fast Gohan's power rises matters (since Veggie said it was increasing). If the fight drags on and Freeza makes him mad, Freeza's cooked.

Also could they damage him enough to defeat his second form? Or does Freeza fully heal?

Vegeta, Krillin, and Gohan can definitely defeat 1st Form Freeza. It's possible they can defeat a Transformed Freeza who has Monster Zarbon's boost.