Let's just get one thing straight, because I don't know where you've gotten the idea about the console going before the mic pre:
The mic pre is for amplifying your mic's signal up to line level. Nothing else. Once the signal is amplified, you don't need to go through any additional amplification stage.
I noticed you have altered your signal chain now which is good, I just wanted to be crystal clear on this:
Going from the board into the pre is a big no-no, unless you're doing some kind of sonic experiment.
When going to your converters, I would recommend bypassing the board altogether - tha board in this case does nothing but add noise to your signal.
For monitoring, I would use the board, but separately from the input chain. To do this, you need to see if your pre has multiple outputs. If so, run one line into the board, and monitor the signal before it goes into the computer/DAW. Use the other line directly into the AD converters.
If it doesn't have multiple outputs, then the going-through-the-board method is an acceptable solution, provided we can work on the gain staging so it doesn't clip your board.
You could also get some kind of buffered splitter to go after the preamp, but a) it would cost money, and b) it would be totally dependent on the quality of the splitter whether it would do less damage to the signal than running it though the console.
Yet another option would be using two mics side by side, provided you own two mics. One mic would then be dedicated to the monitor chain into the board, and the other would go straight into the pre > converter.
It would be helpful to know what gear you are using, this way I could be more thorough in my description. What preamp do you have? What mic? What converters?