I am wondering if I have content sharing turned on for on of my campaigns, and I deactivate a character for whatever reason. Can the owner of that player still utilize the content I am sharing to the campaign?

I have used up all 5 of my content sharing slots. I am currently in the process of ending one of my campaigns, which has only a handful of sessions left. In the meantime, I am working on a new campaign and I already have players creating their new characters. Because I have no content sharing slots left available, I am having them create their characters under the campaign that is ending. 

My question is, if I deactivate the new campaign characters, will they still be able to access all my shared content? Thanks in advance! 

I'm not sure, but why would you deactivate those characters in the first place? I assume you'll deactivate the campaign once it's over and you'll start a new one, in which case the players can move the characters there? Any content that is on a sheet stays on the sheet, even if the owner loses access to it. They just won't be able to add to it (like gaining a level in a class they only had access to via content sharing) until they have access again.

I'd deactivate them from being active members in the existing campaign. When encounter building it's rather annoying to have to select which players are active in combat and which aren't. The whole point is that I want the players to be able to adjust and edit their characters between now and the new campaign starting. Which means they'll need access to the content sharing. I just don't want them to show up in the campaign.

In that case, just test it. The charsheet will remain as is regardless, the players will not lose any work they put in if you deactivate the character.