Drum Replacer How-to Question

It probably is if you filter it. You could either destructively filter out much of the high and mids to just let the kick through. There is a filter on the drumreplacer itself you can try as well. 

I've had fairly good results doing exactly this. There was a bit of extra work involved though. Try setting the Filter knob somewhere around 40-60hz, and that should be mostly kick drum. However, there's more low end energy in snare hits than people often expect, so you'll likely end up with some snare hits detected too. So go through the track and click on the orange markers to turn off any stray snare hits.
 
It's a bit laborious, but it works really well. I've re-assembled a full kit fairly well from a single overhead mic by doing this for each drum in the kit.

try making a copy of the track, then using eq, hi-pass, lo-passs... to get mostly kick.

I would also use a clone ofone of the overheads. If the above suggestions don't get you there you might want to try Melodyne: click on one snare hit, and then select all the same notes in the drop down window. With all the snare notes highlighted, select the amplitude tool, and bring the snare hits down. Render and use the Drum Replacer and /or some of the above suggestions to isolate the kick hits. After you get only the kick hits you may want to drag the track to a midi track to trigger Addictive Drums or Session Drummer.
 
Rocky