No problem at all, Sowainne!
I'm really happy that you want to make a fanfic about Gale. I'm a little sad when I can't write his route (it's one of the stretch goals during my Indiegogo campaign so I did plan his route briefly!)
I will do my best to answer your questions one by one!
1. I'm wondering what a relationship with him would look like in general?
First of all, Kaiden and Gale have simple mindsets. They came from a humble background so their education is limited and can be a bit gullible... Due to that, the nobles sometimes took advantage of them. While Kaiden persisted on trying to gain people's approval, Gale on the other side, eventually developed a wary habit/easy to be suspicious of people's intention (Hence, he didn't hesitate to point an arrow at Maya the first time they met lol)
He will definitely be wary of new people until he knows whether your intentions are true or not.
2. How do they act when they start having those feelings, are they the type to keep it to themselves or do either of them want to take initiative?
Kaiden and Gale have different approaches/understanding about romance/affection. Kaiden used to be the type like Mitra (if you played Winged Ones you'll understand :'D if not, let's say he used to be the warm and fuzzy type, innocent and gullible too). But ever since his personality became twisted... Well, if you played his route, you'll notice that he will test you more than once and rejected your approach countless of times, but once he accepts your, he will be the devoted type. He is very obssessive/paranoid with his partner. Kaiden's love language is skinship, he likes to feel your warmth. He will take initiative as much as you allow him and he will be a very jealous boyfriend that will cover your eyes whenever you try to look at other men.
Now enough about Kaiden x'D
Gale though, is the shy and quiet type once he deems you're not scheming anything behind him. He won't accept skinship on the early stages, but he will give you attention through other things, such as he will give you drinking water when he notice you're thirsty, fill your a bowl of food first before his (this is big since food is considered precious when he was a child, he lived in the slums, remember?), and his eyes will follow your movements. Basically, he will take care of you since he considered you one of his friends now.
Gale's love is the type that is calm and constant. That is, as long as you did the same. Because of his humble background, he is the type that will hide his feelings because he knows there are other people better than him. That can provide better, because he's not the type to chase wealth and content with whatever he has. Because his life right now is much better than the slums and he wants to keep it that way. Therefore, you will have to take the initiative in order to get closer to Gale and prove to him that your love is true and with marriage in mind/to be partners in life, not just a fling. Being constant with your actions is the key with Gale. Otherwise, how can he judge whether you're sincere or not?
Extra info:
- He likes straightforward people that doesn't scheme behind his back.
- Gale likes soft bread, preferably if they're freshly baked.
- He hates dried food or preserved food, because he eats it too often during long-missions or during his days as a knight-in-training. He only eats them because it's cheap.
- Secretly, he likes to stash money/hide some gold coins for emergency purposes. But the main purpose is for him & Kaiden to be able to comfortably retire.
- He doesn't like to cause conflicts if possible, but if someone mess with what he considers his, well, they'll find their lives to be more difficult in one way or another (like getting your requests for help ignored by the 7th Knights Division or have rumors circulate around you). Gale learned how to use rumors to his advantage from the Nobles, though he won't admit it.
I hope I answered all of your questions! If not, feel free to ask more~ ^.^)/