Yeah but you're not exactly the 'target demographic' for the 'appliance' approach GL.iNet designs their SOHO/travel routers for, are 'ya? 
I wouldn't try; you'd end up mixing in GL.iNet's customisations if going GL -> OWRT. I'd say the same OWRT -> GL; weird things can happen. That said (& to sound like I'm contradicting myself) re: VLANs, SSIDs, etc. See the following:
That HOWTO is for the Flint v3 but it should work just fine on your Flint v2 inc. on pure OWRT. Just modify it to account for whatever details like the name, interface you're attaching the VLAN to, etc. The HOWTO uses 192.168.8.1/24 for the LAN, 192.168.25.0/24 for the IOT VLAN. Change'em accordingly for your needs. Recall pure OWRT defaults to 192.168.1.1/24 for the LAN.
Technically yes but not without some initial work — but boy, oh, boy, is it worth the effort. The 'Using a uci-defaults script' section might be of extreme interest to you if you're running multiple OWRT devices: