Hajj e Badal

Assalam u alaikum. I wish to perform hajje badal for a deceased relative. I've performed my own fard hajj but dont have the money to finance this second hajj. I have therefore asked family members to help finance the trip but those that I have asked have not been to hajj themselves. They are all alhamdulillah wealthy enough to be able to finance my trip and still have enough savings to go on hajj themselves but choose not to/aren't in a position to go themselves yet-can they still give money for my trip? will my hajj still be valid? Also although their income is from halal sources, they don't all pay zakat, and some still receive interest (ri'ba) in their bank accounts. Would it be allowed to accept money from them in this circumstance? even if the amount i'm receiving could easily have been earned from their halal incomes and not necessarily be taken from the interest (ri'ba)? Jazakallah Khair. Wasalam