Inter-VLAN forwarding for UPNP and DHCP requests

Hi,

i have a network with 2 VLANs. One for IoT devices, one for "real" devices. Now i have to create firewall policys for two situations:

1. I have a Philips Hue bridge in my IoT VLAN, and a smartphone with the Hue App in the other VLAN. The Hue App uses some kind of UPnP discovery to access the Hue bridge. How can i forward the UPnP discovery from standard VLAN to the IoT VLAN?

2. I have an Amazon Dash button i'd like to play with. This software listens to UDP and ARP requests the button emits when it wakes up on button press and searches for DHCP. I'd like to run the software on my home server in the standard VLAN, and so i need to somehow forward DHCP requests from the IoT VLAN to the standard VLAN, but the requests should still be answered by the dnsmasq running on my OpenWRT box.

Usually i have some knowledge about networks, but this DHCP (UDP or ARP) and multicast stuff is yet beyond my knowledge, so i am kindly asking for help. I do not even know if this is possible at all.