Now that I have some time let me comment this properly:
Harper Sheila, (along with her brothers), are Harper's best friends in the family. That's set! Becky could be a close friend outside the family? They are close in age, after all.
Kylie</a> She and Lucas have a run in flirting type of friendship going on, yes? Miles, Axel and Chelsea are two years younger than Kylie, so maybe they can all be friends? That's not a big age difference. Keira and her can be really good friends? Went through all of school together and maybe even college too? Roommates even?