I'm pretty sure this isn't possible, as I feel like it would bypass some profit options, but I have to ask. Is there a way for me to add a character sheet from my own characters into one of my own campaigns?

This is the situation: One of my players asked for a homebrew race. So I made it from scratch in my account then walked him through the creation process. I'd like to be able to link his sheet to the campaign so he can use it like the other players, but I don't know how. I'd rather not have to walk him through making a race from scratch (the traits were a nightmare) on his account if there is a way for me to just add it as an unclaimed character for the campaign that he can just claim on his account for the duration of this adventure. 

any thoughts?

Yes. Take the url for your campaign, paste it into your address bar and then choose that character when you are asked. I believe that you can then unassign the character and your player can claim it. If someone else could confirm or deny that last, that'd be helpful. But you can absolutely add your own characters to the campaign.

This worked perfectly! Thank you!