I’ve never had a male neutered, so can’t speak to that. With Scully, SHE left her incision alone, but Mulder wouldn’t leave it alone and kept licking it, which of course a cone wouldn’t have helped, so we put her in a t-shirt and tied it up around her waist so that it covered the incision and he couldn’t reach it. Jolie had all sorts of incisions as she had a mast cell tumor removed from her side, a separate mammary tumor and was spayed all in the same operation. We had gotten one of the inflateable cones for her, but she didn’t really need it as she left all her incisions alone.
Chloe is still intact but when she hurt her leg and needed to be splinted for a few weeks, we found the Bite-Not collar which is kind of like a cervical collar for a human to be both effective and comfortable. I think that would be my first choice if I needed something like that.
As for the exercise, we did short leashed walks before 7 days - that would be much better than fetch in the house as you can better control them so they are not doing anything that pulls on the incision like they might if they are playing off-leash (even in the house). Again though, we only had girls done.