The leaks at the head cylinder gaskets to the case are not a good sign of a quality rebuild. I hope you've caught it just in time.
You could damage the machining and never get a good seal again if left too long bouncing around on loose or broken head studs.
Hopefully the last rebuilder didn't ignore old damage. It can be machined again if it's not extreme. Just a light trimming using up some more $ for your credit card!
Do some serious cleaning and measuring. Find any other broken studs?