I want to register (i.e. wish list) a 1st round of a tournament. If there are other sessions on the same day or next, without overlap, do I register for them all? Will the wish list processing add me only to the first one I get in and bypass the rest? 

Or will it register me for any/all that I have during reg period, forcing me to delete the ones I don't want? If this is the case, then what about other events (non-tournament) that I want to select. Will they be skipped because I'm in a 2nd, 3rd or more slot of the same tournament first round?

I hope this makes sense.

The wishlist will let you sign up for multiple first-round slots and you can then delete the redundant ones from your cart before checking out.

Later rounds should not be available to put on your wishlist. They are in the catalog just so you know what time they are, but they are "invite only". It will let you buy tickets to other events in those time slots (but you shouldn't).