2100 questions

I have a 1970 Mach 1 4-speed with a (temporarily) transplanted 1969 351W engine. It appears to have a 1970 automatic 2100 2-bbl on it. It wasn't running right when hot and the carburetor looked all gummy. After reading here and elsewhere it looked like I could tackle a rebuild myself. I got it apart, cleaned, and reassembled but, as I was about to reinstall it on the car I decided to set the idle mixture screws while they were easier to reach. I "lightly seated" one and then backed it off. The second went in almost until it was seated and then seemed to bind. I tried backing it off but it wouldn't go. It would go in however. I decided to try to take it out and check for burrs etc. but I ended up breaking the head off.
#1 Where do I get another one of these screws?
#2 How do I get the rest of the screw out without making things worse?

#3 This car was cobbled together when I bought it and I'm not too familiar with Fords. The small vacuum port under the choke thermostat wasn't hooked to anything. Is this supposed to go to the distributor?

#4 I've read that without a choke there will be a vacuum leak. Mine doesn't have the heat pipe on the choke thermostat and the place where it goes draws in vacuum. Is it supposed to? Is the heat pipe enclosed or open on the end by the exhaust?

#5 The carburetor has a dashpot on the throttle linkage. Can I leave this off since my car is a stick shift?

It seem very possible that my car had massive vacuum leaks and may not have required a carb rebuild (although it seems to work more smoothly now). I'd have just purchased a rebuilt carb but I have a 351 Cleveland going into the car as soon as the rebuild is complete. I just need the car to be drivable until then - hopefully without spending a ton of money.

Thanks,
Troy