Could baby oil 10 days post FUE lose grafts?

Based on what you describe the baby oil should not have had any effect on the grafts.At this point the grafts are firmly planted in the scalp.

It is best to ask your surgeon about post operative care as each doctor has their unique regimen.  

By the 5th day after a FUE hair transplant the new grafts are set in their new home.  It is less likely that on the 10th day you disturbed anything with the oil.  You should follow your surgeons post op instructions regarding hair wash.
We give every patient a post op "Goodie Bag". Among other things, the bag contains a special shampoo.  We ask patients to foam up the shampoo and apply the foam to the scalp.  If the scabs persist leave the foam on the scalp for several minutes to soften the scabs.  Do not pick at scabs.  If by 10 days scabs remain you may keep foam on scalp for 7-10 minutes then rinse.

While you should not rub the recipient area for 14 days following your procedure it seems very unlikely that you have caused any damage. If one can tolerate a "greasier" substance we recommend to our patients to spray either baby oil or coconut oil in the recipient area (instead of saline solution) during the recovery period.

if baby oils is applied at 10 days, it should not impact the grafts, especially if there were no crusts on the recipient area