Once you have ATK Up 10, you can already shift the Medic to the front lines to be a "Combat" Medic (and/or probably having some HP up). Caduceus is pretty much your only offensive skill but personally, you do not have to get it that soon.
Whatever Medic you want to make, the only priority you ever need is to get Immunize 10 (Even without the Protector's Defender or Troubadour's Shelter). You will be thankful for it.
Skills that you can forget about:
Patch Up
Scavenge
TP Regen
CPR
Regen
Healing Touch / H.Touch
As for Refresh/Unbind/Revive, ditching them really depends on whether you want to use the consumable items of the same effect. If you are using the items, you can neglect the skills.
Extra note:
If you are going to have a Troubadour in the main party, try to get Relaxing 10 as soon as possible. It will make exploration and FOE/Boss battles easier since you can regenerate TP over time. You could afterall enter a simple random battle, cast Relaxing and have everyone Defend until you regenerate all the TP you need. Healing/Immunize/Shelter/Defender is a bonus.
