@wondering 

You have a relatively small network and your APs should be DHCP configured anyways by the OC200.  Should be a simple matter to reconfigure the IP of the printer if it's static.

My recommendation is spend the extra few minutes to move your system over to the 192.168.0.x network, it really shouldn't be a big deal and will make your life easier in the future (like if you ever replace the router)

Here are my thoughts on how I'd do it, system will be offline:

1. power up the factory-reset Omada router in standalone mode  (let's assume you'll have router at .1, switch at .2 and oc200 at .3)

2. attach your laptop to the LAN port and log into router and configure a Fixed IP for the MAC address of the OC200 (or skip this step and figure it out later from the attached clients list on the router)

3. unplug the laptop and attach the switch to the router's LAN port, then login to your oc200 at it's new 192.168.0.x:8043 address

4. Edit your LAN subnet from 10.x.x.x to 192.168.0.x/24 on the Controller and add Fixed IP mappings for your switch, the OC200 and your APs and printer if desired

5. power cycle the router, switch and oc200

6. log back into your OC200 at it's new fixed ip and adopt the router

7. Verify that AP's have come up with 192.168.0.x addresses and wirelessly attached clients can ping the router (192.168.0.1)

You can connect the gateway in either router or bridged (preferred) mode to the WAN port of your Omada router now.  You probably want to configure WAN for a IPv4 Dynamic IP which should be the default.