Breadth, Depth, or Both? (ECs)

Since the commonapp provides 10 slots for ECs, is it okay if six of my ECs are related to my academic interest and four of my ECs are related to other genuine non-academic interests (no fluff)? I know that there is no “formula,” but I would greatly appreciate your input.

I don’t have many long-term commitments (i.e. > 4 years)… will this detract from my applications for T10s-T15s?

Are you perhaps hinting at unique hobbies being particularly helpful in T10-T15 admissions? If so, do they want to see you pursuing said unique hobbies independently or with a group of other individuals?