I completely adore my cat, and he's very affectionate. However, we are having some issues, and I'm a first time cat owner and not sure how to handle them. I would love some ideas and advice.

1. FOOD: He's SO hungry all the time, and I'm not sure what to do. I give him two 3-oz cans of Fancy Feast each day (morning and evening), but he begs for food all the time, and started getting into my kitchen cupboards and snatching any food even briefly left on the counter, and he always tries to steal my food while I'm eating it. He's not thin, but I think not too chubby. Just has a bit of a belly. When he's particularly hungry he nips at my ankles and meows a lot. Sometimes I do give him a little extra dry food mid-day between his meals. I don't want to let him get overweight, but I also don't want him to be too hungry and I'm not sure what to do.

2. ATTACKS: He cuddles a lot, and also bites kind of a lot. The bites are usually not too hard and I think it's mostly an attempt to play. BUT, sometimes it escalates. Depending on how we respond to his initial bites (usually the typical thing of wrapping himself around a hand/forearm and chewing a bit on the arm or hand), sometimes he goes into what appears to be actual attack mode, launching himself at our heads/faces with his claws out. When that happens I generally bat him away pretty firmly and then he leaves me alone. It's so unpredictable and a little scary though! Last night he was being super affectionate, purring, head-butting, then attacked my arm. I was ignoring that for a few seconds, then he launched himself at my face and ended up scratching my eyelid. I am guessing that he's maybe a bit understimulated. SO, maybe what I need is some advice on how to play with him/ keep him stimulated enough??

3. NEUTERING: He was neutered before I adopted him from our local shelter, but when I picked him up they gave me a note saying they only found one testicle, and to bring him back for an additional surgery if he started displaying "male characteristics" around six months. Seems like they were unsure if he only had one testicle or if they just couldn't find it. What characteristics should I be looking for? Are the attacks I described above maybe because he isn't fully neutered?