Welcome to the forums. As I am also a new team, I cannot give personal advice. Though, I can relay info that I have heard and plan to use.
In my opinion, no less than 3, no more than 6. 4 is the sweet spot.
If you are talking about finances, it’s not a great idea to have teammates pay for the whole team. Look into sponsors, ask for money from your school, and do fundraisers.
Practice as much as people are comfortable. 3-5 practices a week is good.
I know there are grants, look at their website.
Talk to administors and stem/computer teachers. You don’t NEED a field but you will be glad to have one.
Along with all this, check out these resources.
Hope you find what you’re looking for!