Several issues you may want to think about.
There are vast differences in the design, construction and implementation between a DJ system versus a home theatre.
Isn't DJ equipment portable? How does moving the entire 5.1 package, plus the requisite mixer and multiple sources, fit into your plan? Most DJ's generally get by with two large speakers. Now, here you are with at least six.
Second, a DJ is required to move a LOT of air. This generally requires decent size speakers. Speakers designed for DJ use tend to be designed for maximum volume and projection over a limited range in order to fill a large area with sound.
Third, the power specs on HT receivers are over-rated. Not to drag up the "all channels driven" controversy again, but this is exactly where they fall short. ...in striving for maximum volume from all channels simultaneously.
That 5 x 100 watt receiver which will only sustain maybe 40 watts per channel when all channels are driven, while more than adequate for home HT purposes, will be driven very hard in a DJ environment. Even if you only used two channels, it will still be hard pressed to deliver constant high levels of sound.
Do you still want to consider this route?