So in the 1st question - after performing the Cliffhanger next turn - the turn simply ends with no further adventuring (nothing to adventure), no die rolling to Move because you're still stuck at the Cliffhanger - OK sounds like a plan!
If a Hero fails a Danger and flips to a Cliffhanger while at a Temple, immediately remove any Danger Markers currently on the Temple and add another Instability Marker directly, rolling for Collapse straight away.
When a Temple Collapses, discard any remaining Fortune coins on that Temple, remove the Temple figure from the board and discard the Artifact Adventure Cards. Any Hero in the Space will now have to try and Escape (even if he hasn’t found the Temple or is at a Cliffhanger or a collocated Outpost)!
In the lower right corner of the Temple Artifact card there is an Escape Test. Every Hero in the Space must pass the Escape Test or be KO’d. It is important to note that Heroes (as well as their Team mates) may Exert to add extra Adventure Dice to an Escape Test as detailed in the Skills section of the rules. If a Temple Collapses, the Hero immediately gets any pending Glory for Dangers that were overcome this turn—unless the Collapse is due to going to the Cliffhanger: then the Glory is lost as normal.
Even if the Hero escapes the Collapsing Temple, you will still need to resolve any pending Cliffhanger in your next Adventure Phase. If an Active Villain is at a Temple that Collapses, he takes D6 Hits (Defence applies) and Returns to Base in either the Delayed State or the KO’d State. Inactive Villains are returned to the deck. Acolytes are removed.