I enjoy this
To start with the last: sailplanes are no different from other aircraft, they normally don't have an engine, so their energy management is using altitude. If you want to go fast, lower your nose. Want to slow down? Get the nose up. I'll let you in on a secret: I have flown them too. Of course
they have speed-brakes, but that is for bad planners and landings in tight spots.
Back to the post:
When I turn back into wind, will I need to reduce power and raise the nose?
That will depend on what you want to do. If you are in the traffic pattern, get your airspeed right. If not, take your time.
The aircraft does not know what the wind speed is, so why would it's flying characteristics change? It surely has to be something to do with flying relative to a point close on the ground, unlike to a distant horizon that you use for basic training?
The aircraft does not care about wind speed or ground speed, all it knows is Indicated Air Speed, IAS (and of course for you nerds CAS and TAS).
The flying characteristics changes only with air speed, not wind or groundspeed.
Is this also true of a fixed wing aircraft doing a recce of a point over ground?
Helicopter, fixedwing, spaceship- same thing (I think)