I am sure that there are other topics covering this but I have been banging my head on my keyboard trying to just get this to work.
Whenever I have gotten the VLAN's set up, everything goes smoothly until I try to set each VLAN up with their own DHCP server and then I get a DHCP configuration issue.
Any guidance would be much appreciated (or links to topics that cover this that I am not able to apparently find).
Whenever you use VLANs, all devices seeing those tagged packets must be VLAN aware, which means managed switches (especially with only 1+1 ethernet ports, if you had more ports you could do a poor man's VLAN setup (dedicated access ports on the 3-4 lan ports, one per VLAN, and unmanaged switches from there on)).
To put it more directly: a managed switch is required for VLANs.
The behavior of VLANs through unmanaged switches is, by definition, undefined. Some will pass the tags transparently, some will strip them, some will choke entirely and break your network (and sometimes the problems can even be more subtle).
Without a managed switch, you cannot connect non-VLAN aware devices to the desired network because you cannot control the port-vlan membership and tagging. There are other issues that arise as well.
But one could create vLANs at the OpenWrt router and use them for e.g. an isolated guest network. So it depends on the use case, doesn't it?
Check if you have vLAN capable HW in your device
(scroll down a bit)