I thought the principle was "We won't put you with a team you played twice, period; and we'll do what we can to not put you with a team you played once." If the switch is as simple as swapping two of the same seeds then I imagine the committee would do it. The issue might arise if, for example, 3 seed Iowa State had played all four of the 14 seeds in non-con.
I could be wrong, I'm just going off of memory.
You're pretty much correct, if I'm recalling rules correctly -- they have those rematch guidelines, the intraconference principles are followed "unless it's unavoidable" and the regular-season non-conference rematch is a "strive to avoid" situation. And like you said, since it's a simple swap, they'd probably do that. It wouldn't be a priority (so if all the other 14's were either also rematch or were maybe placed far closer to home than a 3, it wouldn't be switched).