A 71: Some of these fall into the fuzzy gray area. By strict interpretation, nothing overlaps. However, I would rule that external effects would stack (entangles, walls of fire, etc). As for Hold Person and similar, only one spell effect of that name can affect the target. This was implemented to simplify certain things in the rules, but also leads to stupid workarounds like casting resist energy on an enemy which already has that buff active, changing it to something else so your teammate can nuke him.
A 72: You have to make saves for each.