You should adjust the idle mixture screws per previous instructions. If you don't feel secure then count how many turns it took to bottom them out and remember that so you can always back them out to original position. And don't screw them in super tight ! The tips of those screws are pointed and fragile. Hopefully, the idle will come back up the 200rpms you needed. As for the curb idle screw, the missing threads and flattened tip seems strange like someone grounded it down. Can you guestimate that if the missing threads plus the raised tip were restored, the curb idle screw would be just the right length you needed ?
Good Luck.