Few options if that indeed a requirement to have unified path:
As you said - DFS. we have DFS fronting the File servers with just referrals. no replication. It’s working. We also use it for our DR failover (based on snapmirror). It works OK the only problem start with our helpdesk not being able to troubleshoot it (they can’t “just ping”) and we had some nightmares with getting branches and subsidiaries to use it (mainly political around firewall and exposure).
BranchCache – I don’t like it. But it works.
Symbol links on a dedicated “root share”. You can create a single share used by everyone on one or both the clusters - from that share you can create symlink either locally or to the remote cluster. * In one of the places I worked before we has different DNS subdomain to each site. It allowed us to create the same record name on each site and refer to different targets (so \\fileserver on one site referred to one server and on another site to completely other and the client picked it as it was registered in the same subdomain and first in the FQDN search. It was good fun and allowed something similar to what you asking here without the need to travel around the network
Now that was all to meet that requirement. Is it a real requirement – you only know.
I’m an old fashioned. I prefer single CNAME to single purpose and that’s it. No extra point of failures and management. Easy for helpdesk/network/partners to understand and troubleshoot.