Need help with Jamis Bosanova

Hello everyone!

I haven't had a bike since I was a kid and decided to pick up this Jamis Bosanova 51cm for 300 AUD (hoping I didn't get ripped, but I don't think I did) and I love it. Don't know a whole lot about bikes and have a few questions, so I'm hoping I can get some answers here:

1. One of the spokes on the rear wheel is broken, how much will it cost to fix?

2. There is a small chip in the paint, how can I fix this so I can remove and prevent rust? Is this easy to do? Also how much?

3. I read somewhere online that the disc brakes use a dead standard and it's hard to find replacements for it. Ideally I would have liked to swap parts (any part not just brakes) and not be tied to a specific standard/proprietary parts. How realistic is this?

I am happy to do all repairs myself as I'm quite handy, but only if it's realistic/easy to do so as I don't really have any bike tools available at this point in time.

My plan is to convert this into an ebike after a while, but I want to have some fun with it first. Maybe if I like it enough I'll keep it as is and get another bike for conversion, but I'm undecided as of right now. If anyone has any pointers/tips that would also be greatly appreciated!

And last thing, if someone was able to point me to what year the bike is so I can find out more information about it that would be awesome.

Sorry for the long post, but I'm a little in the dark here and would love some guidance.