So through all of this I have not heard of Gizzy going to the vet to see if he is 100%.
Have you considered adding another litter box? Not in the same area the other ones are in. Maybe across the room or in another room all together. I know it's a open concept condo so maybe one of the bathrooms? Do you clean them morning and night? Are they away from noisy appliances? Is Gizzy being ambushed by Forest when he tries using one?
It is also possible he is still able to smell his urine on your bed and therefore has decided it's fair game. You may need to wash all of your covers/blankets in lots of vinegar and rubbing alcohol. The mattress you can try renting a carpet cleaner with a furniture attachment and clean it very very well. You may have to sleep elsewhere for a night while it dries but it's worth a shot.
If none of this works then pm me. We can work on something. I just hate to think of him being given up for spraying. Although I am still not sure if it's spraying or peeing.