Yes, there's no problem in this if the transaction is at Arms Length Price. Please like my reply if you are satisfied so that I will be motivated to answer more
Yes HUF can purchase from members. However Arm's length price is for associated enterprises having domestic transfer pricing applicable. So there is generally no need of confusing the queriest with fancy terminologies.
Practically, ensure that there is a reasonable margin of profit in the books of HUF so there is not much complexity. Also, report the purchases from related parties in tax audit report if applicable.
Request everyone to reply to forum queries only if they are sure of the answer.