318 2bbl won't idle without choke

Slap a timing set on it and then check compression. That will tell you if it's worth sealing the engine back up.
The oil pick up has a screen, so that nylon likely hasn't gone any farther than the pickup - sub optimal situation, but the engine is likely serviceable even if you don't find those chunks.

Personally, I'd still want to drop the pan. The amount of crud on there suggests the pan is full of all kinds of crud that would be best to remove. But dropping the pan in-car is not something I'd want to do, either.

What's your intention with the car?