Can Android and/or Apps handle switching an SD card temporarily?
AFAIK it is very difficult for an App to identify the inserted SD-Card. A regular App should be able to handle the case if the SD-card is not available (ejected or connected as drive to the PC via USB) but I assume that most Apps can not handle the case when you regularly switch between two SD-Cards.

In general you should not start any Apps that use the SD-Card while you have inserted the "wrong SD-Card".

Regarding the Apps moved onto SD-Card - this is a different topic. As my device does not allow to switch the SD-Card while running I have no clue what happens e.g. to the app data in your device if you switch the SD-Card.