DSP for HT & 2-channel?

Well, nulls may be unavoidable, but especially for the bass, measure your sub at 3 locations. Also, check out the room simulator in the link below and attempt to keep both your sub and listening locations out of the first few nodes.  The best techniques are to use placement, bass traps and DSP together.  If you can't do that then do what you can.  The bass traps help the DSP work better by de energizing the room modes, like damping a bell.

Lastly, GIK acoustics soffit traps can really help smooth out bass responses.

Yes, DSP helps a great deal with 2 channel. No noticeable delay.

https://amcoustics.com/tools/amroc

I was able to eliminate nulls with placement which (easy enough) was to put them the corners next to the KEFs  What I'm dealing with now is an uneven frequency response according to REW despite my best effort of placement.  

I measured 3 different locations and blended the graphs to setup the subs. 

Here's a quick description of the measurements:
20-70Hz, consistently in 85-90SPL

70-135hz, SPL dives to 75

135-200, recovers up to 85ish. 

I'd like to even out the frequency response.