New clutch setup won't disengage

Firstly, you won't hurt the ring or pinion with the starter (If I understood that correctly)
I had a car that sat do that once and I blocked the pedal down and reached in through the fork opening with a long screwdriver and popped the disc loose, and everything was fine after that.
In your case you may have to pull the clutch out and reassemble it if you are not comfortable or able to do anything else.

Personally I'd be tempted to warm it up a bit to make it more agreeable then roll it out in the street, put it in gear and fire it up.
Of course you need to be ready and understand that it may just take off with the clutch in, but you can pop into neutral if needed.
It may come loose right then, or you might have to push the clutch in and jump on it a little.
I'd try that as a last resort before pulling it and reassembling.

I had to drive a car through town and about 15 miles home with a broken clutch fork once and I basically did it this way.
Put it in gear and fire it up to get it rolling.
Pop it in neutral at stop lights and stop signs and shut it down, then put it in gear again.
Then the light turns green and you fire it up rolling again.

What you want to do is fire it up in gear with the clutch in and jump on it a little.
It'll come loose if it's just stuck, but won't if it was an assembly problem.