Thanks for the tips and ideas for my issues with Kowhai over the past few weeks everyone. I am pleased to announce Kowhai will now go into his cage of his own free will and will let me take him there (for the most part) again!
Having his food be only in the cage was a big help, and also, I moved his cage to my bedroom rather than the living room. Before he would just sleep in his small cage in my room, but now he sleeps in the big one, and just spends his time in the living room on the various branches and play gyms I set up for him.
It's so nice to not have that issue worked out.