Will an IPv6 DNS Server Respond With IPv4 Addresses? Can the 2 Protocols Coexist?

[Gerowen]

Let's say I've got both IPv4 and IPv6 working properly on my network.  I have a PiHole and I've reserved both its IPv4 and IPv6 addresses in the DHCP pool, and added those IPs as DNS servers in their respective DHCP settings so all the clients know there's an IPv4 and IPv6 DNS server available.  Now let's say a client requests resolution for a domain name, and does it over IPv6.  But the only DNS record available for that name is in IPv4; will the DNS server respond with that IPv4 address?  Will the whole connection get downgraded to IPv4 if there is no IPv6 address that can be resolved for a given hostname in the DNS request?  I'm just trying to learn how IPv6 is going to impact my ability to adequately run my home network and continue using my PiHole to control internet access for my kids' devices.  Should I just disable IPv6 altogether, at least internally?  I considered that, but even when I turn off the IPv6 DHCP server, many clients are auto-negotiating their own IPv6 addresses and using those to communicate directly with one another, despite not having a mutually agreed upon DHCP server.  It's my  understanding that this is expected and normal behavior for IPv6 unless I go to every single client device and manually disable IPv6, so it seems more reasonable to learn how to work with it instead of constantly fighting against it.  I'm also curious, when my ISP ever gets around to actually using IPv6 and giving us a public IPv6 address, will that change the IPv6 prefix my router is using, and therefore also change my internal IPv6 addresses?

[d5aqoëp]

DNS64 from google allows you to access IPv4 only sites via IPv6

Check this out if it suits your needs

https://developers.google.com/speed/public-dns/docs/dns64