Yay for new tanks!
Do you have plants in mind that you'd like to try? Or an idea of what the tank will look like? For example, do you want a lawn? Are there tanks you've seen that you'd like to emulate?
I have several 10gs that are planted and I just use the stock lights that come with them. Decent lighting enough to grow ludwigia and all the low light classics.
I have also tried keeping a betta sorority in a 10g. It didn't last and the girls did much better once I moved them up to a 20g long. That being said, I don't recommend a long-term betta sorority in a 10g just from my experience. 4 or 5 bettas seems like a lot for one small tank too.
Looking forward to seeing your tank come to life.