I forgot one more test: the RUNNING compression test. It is a bit of a pain to run (hot engine), but can reveal some things that can be missed on a cylinder leakage test. Lifters that are pumping up too far (but only with the engine running), and holding a valve slightly open.
Had it happen to me when somehow the lifter lost its wire retainer for the pushrod cup, and had unlimited travel hydraulically.
Hopefully, the intake leaks are sealed now, and a second vacuum reading is in order.