I say chaps (etc),
To my untutored brain cell:
0: Getting under/over and close with the drone to be refueled is fraught with difficulties.
For laser transference probs, see 1 below.
1: Ye boom method of energy transference is prob' best for present as 'little misses' with lasers can lead to big whoopsies.
2: Speed matching and turbulence 'wash' is the villain of the peace.
3: Ye drones come in basically x2 flavours ( / flavors if you're colonial ) + sub-flavour smaller versions of A below, viz:
Planing + Hovering.
A.0: Big Bugger like small fighter size - Usually IC engine of some type within.
Way Forward:
Bring to stage where able to look after itself and take on fuel (leccy or liquid) from tanker boom.
+
A.1: Smaller bugger version of above.
Way Forward:
Pref' as/above.
If they can't be brought forward (thought most prob' the case) because of speed + stability issues when maintaining station behind Big Hairy Bottomed Tanker (BHBT) then . . ......
How's about small slave tankers launched from BHBT's or in-flight docking to BHBTs?
+
B.0: Leccy + IC driven smallish buggers which have multi props and are essentially helicopter / hovering thingys by nature.
ie. No way can be refueled by boom from BHBT due to lack speed matching ability and inability to cope with BHBT wash.
Way Forward:
Small slave tankers - as/above.
Do hope I've not got too technical for you ( / y'all for the colonials).