Answer: Yes
Explanation:
Yes, you can run different system voltages in the same conduit and boxes. The conductors must be rated for the highest voltage present and used on all circuits.
You need to get final payment for the cabinets before they enter the home. then bill for the installation the day of instillation and collect the check before you leave if possible
No, once installed they become part of the house, you can not remove the kitchen cabinets or any other cabinets that have been installed without the consent of the home owner in writing. if you are a good contractor why would you have to take the kitchen cabinets out of the house anyway. But if you have to you can take the doors.