LED lamps will work perfectly on a wire wound halogen transformer. You do not need to consider a minimum load, even with one bulb things will work fine.
If a dimmer is used, there may be compatibility issues between the LED lamp and the dimmer. This may lead to hum, flickering, erratic dimming, ...
Particularly with dimmers of an older generation, such problems can occur. Today, there are universal dimmers on the market that allow you to choose the dimming programme that gives the best result with the LED lamps.