I'd rather do the reverse if the amp isn't FRFR and the signal is prior to the amp - the amp gets the signal without EQ, FOH gets something that sounds like an amp.A second feed would have to go to a second channel. There are no inputs on the mixer other than channels. All other connections on the mixer are the six aux outputs & the L/R main outputs.
Your suggestion has me thinking outside the box. I have a Fishman platinum EQ with an XLR out, 1/4 out that is varied with the onboard EQ, and a tuner out that is pre EQ. I could set it near my amp and send the tuner out to my amp input and send the regular EQ affected output to a second channel in the mixer. The second channel will be the source of my bass to my aux out channel. I think it will work.
Too often, pre-amp DI sounds awful, IMHO. None of my basses, active or passive, sound good that way apart from the fretless ABG with TI flats.