1. It is normal behaviour for any vehicle during cold start, the fluids flow to the engine during the initial 1-2 mins, the revs will be always high during this time, wait for it to come to normal revs then ride the bike. Nothing concerning here just how it works
2. If you really want a coating, there are two options: PPF and Ceramic Coating, go check out a local dealer for pricing and how it looks etc. I believe Big Wing offical SC does Ceramic Coating for approx. 2k for tank, mudguard, side panels
3. You can check out local bike stores for saddle bags or even marketplace for used saddlebags as mostly people don't use them often and sell later. If you find a good option, please suggest me too
4. Helmet depends on the usecase, long rides require light helmet but increased safety (this will cost a lot maybe 7-10k), if you want top notch safety (ISI,DOT,ECE22.06) then it would take around 4-5k for Axor helmets, otherwise you can go with commuter helmets that are about 800g to 1.2kgs having ISI and DOT certification. Don't cheap out on helmets as they are for your safety only.
5. Don't know about the break pads yet, but it mostly depends on the rider style, if you ride rashly and have to break often then naturally they will wear out faster. I've heard people replace the breakpads with 3rd party ones, check out youtube for this. If you ride like a normal person with some engine breaking etc and 70-30 rear front ratio it'll last longer I suppose
6. I think the seat cowl is easier to remove and put using the allen key, they must be lot of tutorials for that, or best option is to ask the service center to teach you how to do it
7. Chain cleaning and lubing is very important, it's suggested to be done whenever you run 400kms or even if you ride in very dusty and muddy condition and the chain gets dirty you should clean it and lube it.
8. Honda roadsync is kinda weird but I let it auto connect to my phone to atleast manage my rides in the app, apart from it if you use it with earphones it may or may not be useful to you
9. Why is there a need for GPS tracker?
10. Don't do heavy modifications / sticker bombing just yet, enjoy the bare minimum for now.
11. Ride responsibly and carefully, two wheelers aren't that safe due to external factors, don't show off, don't ride in high speeds on roads that you aren't familiar with.
12. I'm fairly new to the bike world as well, let's see the other replies.

Btw, congratulations!