Sorry to hear that you lost your first lovebird, RealKitkat. What happened to him/her?
Your little guy is actually better off without another lovebird around, in my opinion. It makes it about twice as hard to train and socialize them when they have another bird to bond to.
From your description, I would say that your little guy has not been trained to the Step Up command, etc. A wing trim by your avian vet (free flight is dangerous and hampers training) and working with him for 2 15-minutes sessions each day, every day from now on, will help curb that propensity to bite. Birds bite for two reasons: survival (includes fear and horomones and pain etc.) and control. I have a hunch that your lovebird may have started out biting from fear. If you've had him long, it will progress to biting for control. Putting a towel over your head is not training. A copy of Mattie Sue Athan's little book Guide to a Well Behaved Parrot would probably be an immense help to you.
Your little guys diet should include pellets, a few seeds, veggies, fruit, and any people food that doesn't contain sugar, fat, or salt.
Good luck with the training, etc. Keep us posted on Kiwi's progress. We do care.