I have my shelf on hold for a bit to whittle away at my TBR pile. I'm so easily tempted when I come on here.

If I have the only book in the system and someone wants it while my shelf is on hold, does that mean the book would need to go on wishlist until I take my shelf off hold?

if someone puts a book on their WL that you have but your shelf is on hold, they will not know that a book is available until you take your shelf off of vacation hold.  so they would be 1 of 1 on the WL for that book.

hope that makes sense!

I put my shelf on hold a lot for the same reason as you and twice that has happened to me.  I've taken it off hold to post a WL book and another book on my shelf comes up as WL hold.  I think if you look at your shelf it'll put the W next to a book that's WL, while your shelf or the book is on hold.