there is no wrong mic....a mic can cost from $10.00 to beyond $$$2000.00!!!! you should ask dynamic VS condensor!
the 781 is an excellent rig, the behringer stuff you list is also outstanding! you should route your audio through the balanced modulator via the rear din jacks. the mic input does cut and limit some audio frequency response.
be sure to use balanced [xlr] cable and double shielded cable for the audio stuff.
for some interesting and informative discussions about fidelity audio, check out the websites of w3oz and nu9n.
if you can stop by 14.178 for additional help do so.
I use an ic-775dsp and behringer gear with an audio-technica dynamic vocal mic less than 50 bucks!
any other questions?
my e'mail is: firstname.lastname@example.org