I don't think you are going to face any kind of interference with your approach, if I well remember someone has successfully used rj45 connectors for the same purpose.
For sure you will save time at first, but you have to deep investigate in the always-possible-case that something won't work properly. But it's obviously up to you.
I'd suggest you to make a test, wiring a single D-SUB connector with some valves/sensors wired and then spend some time to see if everything is ok.
Good luck with your build, please do keep update here on this!