i still can't figure out rindo... is she on yukihira's side or not...or is she just doing ...

The latter. Rindo has always been the effervescent neutral who does whatever she wants. The reason why she voted for Azami to be the new director of Toustuki in the first place was due to her intention to make things more interesting. She must have believed the new administration would create more dishes that she likes. If she was to lean more favourably toward Soma, she would be the major force in the Elite 10 to veto Amazi's position.