Conditional Forwarding to redundant dhcp?

My layout is like this:

DC1 - x.x.x.20
DC2 - x.x.x.21

each has a load balanced replicated DHCP scope on it and are on different hardware so i can tolerate failure

PiHole1 - x.x.x.70
PiHole2 - x.x.x.79

as above, different hardware

My lease scope has .70 and .79 as the DNS in the options.

I would like to use conditional fowarding for multiple VLANs and set it up for redundant

VLAN1 - handled by the DC1 and DC2
VLAN10 - handled by firewall x.x.x.254
VLAN20 - same as VLAN10

gonna make up fake scopes here

VLAN1 = 10.20.1.0/24 so the conditional forwarder would be 10.20.1.20 and 10.20.1.21
VLAN10 = 10.20.10.0/24 so 10.20.10.254
VLAN20 = 10.20.20.0/24 so 10.20.20.254

the goal is to get hostnames not just IPs

right now DNS queries go upstream to .20 and .21 only, no others

See Conditional forwarding - #3 by Bucking_Horn.