Welcome! I know how that pixie cut and dye life feels, and I can give some anecdotal answers to your questions <3

I also have frizzy hair, and have experimented long term with using and not using silicones. I find that they not only help tame frizz, but prevent a lot of damage. Without them, my hair will tangle the minute I take it down, but silicones keep it slippery and allow me to detangle with ease and without breaking hairs. I'd love to go full herbal haircare, but I just haven't found it in the cards.

As for scalp oiling, Shelomit said it right. It depends! Coconut oil on my scalp leads to a lot of shedding so I don't use it, but some people find it really hydrating. There's a little motto here that goes "YMMV - Your mileage may vary." Everyone's genetic makeup and therefore hair is very different. We try to give the best advice we can while taking into account different hair types, but at the end of the day it's all about experimentation and finding what works for you