I don't think that part of companion behavior has changed, so it would probably have been better to ask in the Gamplay questions section.
I rarely interact with companion inventories, but I think you can "trade" with them to take back what you gave them, with them refusing to let go of some of their private items, although your items being equipped might be an issue.
Anything you've given them that remains in their inventory when you release them from service counts towards their payment, so most of the time I don't have to pay anything extra after hiring companions for robber quests, because the pile of weapons they requested (why do they need 5 axes?) together with the food they also required is more than enough.
If you use your companions as mules to haul items you obviously have to get them to release the items via "trade". I don't know if such items (planks, small tree trunks, herbs, and what have you) would have any value when the companions are released from service.