With high places activated, do you have to have characters of matching brigade to play place enhancements?
I have always ruled that you did. Just like Hidden Treasures allows you to play an enhancement, the rules of brigade matching still apply. I could be wrong, though, since YMT Rules rarely follow standard rules.
Also, would interrupt the battle and ignore beat immunity?
You can interrupt an immunity. FYI, interrupt the battle will only interrupt immunity on characters and enhancements.
An ignore will beat immunity only if it is played
before the immunity. If ignore is played
after the immunity, then it is a stalemate.