Hello.
Let me see if I can help you with some of your questions.
I really don't think filling him up on fruit will help alleviate the night time hunger as there really isn't much substance to it, so I wouldn't go overboard offering fruit. Offer what you usually do, but don't start trying to get more into him. If anything, eating only fruit might give him a tummy ache!
Sounds like you're doing the right things by offering a good variety of foods, different tastes and textures. Keep offering, and keep offering the finger foods. It's ok if he plays with them, that's all part of the process. As long as you are giving him lots of opportunities to eat, then he will get it eventually. What he eats though, is really up to him.
If he is really, genuinely hungry at night, then you could feed him. It's up to you really. If you feel he is eating adequately during the day but is still hungry, then I would feed him. It could be a growth spurt, and may pass after a few days. Of course you don't want to create a feeding habit at night, so keep an eye on it.
It looks like he's already at the high end of milk intake, so I would be inclined not to offer him more milk during the day. I think the normal range is around 24-32oz, so I wouldn't go much past that or else he may eat less solids.
Hope that helps for a start.