In need of tips and recommendationa

 So I (16 nb) am a semi new rabbit owner my baby Cory is only 11 months and I've had him his entire life but I need help. 
  My big question right now is if I get him nudered he is the only rabbit I own currently. originally it was him and his sister who sadly passed away in February. I don't see any need to nuder him now that it's just him but I was wondering if it would be better for him if I just bit the bullet and got him fixed. 
 The next thing is feed I don't know if the feed I'm giving him currently is okay I believe it is but you can never be too sure. Right now i'm feeding him "home fresh, family hutch 17" it's a pellet feed I don't have the budget to feed him fresh veggies every day.
 I also need help litter training and harness training I just need tips for helping him go in the litter box more often than not and tips for getting him to actually move or want to explore while he's on the lead. 

ANY OTHER ADVICE IS GREATLY APPRECIATED