The DH200 is a stereo amp and the DH300 is a mono amp. No preamp there.
Since the receiver doesn't have any line level outputs (except sub and zone 2) you would need one or two speaker to line level converters. https/www.crutchfield.com/p_142LOC80/Scosche-LOC80.html
If you have two DH300 and one DH200 use the 300s for the front L/R and one channel of the DH200 for the center. If you have one DH300 use that for the center and the DH200 for the front L/R.
You will need to redo the speaker level set up on the receiver.