The recovery cost is, specifically, the number of supplies needed to restore a single deployment's worth of lost CR.
Scenario 1:
Costs 5 supplies.
Scenario 2
We actually don't have enough information; that will run you either 15 supplies (to recover 60% CR) if the wolf was at 10% CR after the battle was over, or 17.5 supplies (to recover 70% CR) if the wolf was at 10% CR when the battle ended.
The difference there being that the CR cost of deployment is subtracted -after- the battle ends.
Scenario 3:
This runs into a special rule designed to prevent the player from cheesing the CR mechanics: if one side deploys a vastly larger force and wins the engagement, then their ships won't spend the full CR cost of deployment. There may be other requirements for triggering this mechanic; I usually only see it come into play when I deploy a single flagship, blow up as much of the enemy fleet as I can before my CR runs low, and then withdraw.
So the expected supply cost for this scenario is probably less than 60, but certainly no more than 60.
Other Effects:
Armor and hull damage can, in some cases, cost supplies to repair. ...And in other cases, it doesn't. The specific mechanic here is that armor, hull, and CR all take time to recover - but all of them also recover at the same time, and recovering more than one type of thing at once doesn't cost extra.
So if you take a bit of armor damage, and it takes one day of gametime to repair the armor, but four days to recover the CR you lost, then there's no extra supply cost for the armor damage.
If you take a bunch of armor/hull damage and it takes eight days of gametime to repair the ship (but the same four days to recover CR), then you end up spending supplies equal to twice the CR recovery cost.