I just retired my old miniDV camcorder (actually it is an ennEUtered Sony TRV320E which just uses Hi8/D8 tapes instead miniDV tapes -- otherwise it uses miniDV standard). I used it a lot with PowerMacintosh 8600/200, PowerBook G4 and finally Mac mini Late 2009 and iMovie 1.0.2-2.1.2-6.0.3 and System 9-OS X 10.3-10.11 via Firewire 400/800.
iMovie HD 6.0.3 still runs on my new Mac mini 2018 and macOS 10.14 and I might one day try how the import/export works with the camcorder.
At least old Firewire drives work:
I had two old NewerTech drive docks I had used via FireWire 800 with my old Macs. I connected them to the new Mac mini 2018's Thunderbolt via two Apple's adapters (Thunderbolt 3 (USB-C) – Thunderbolt 2 & Thunderbolt 2 – FireWire). The Firewire drives worked perfectly and I could also boot from them. But occasionally and very randomly the LG UltraFine 4K 23.7" Thunderbolt display went black for a few seconds, sometimes a few times during a few minutes which was very annoying. Sometimes me or somebody else just moving nearby (without moving the desk or the cables) seemed to trigger the error and I suspect automatical display brightness might have played a role there.
Those two adapters were clumsy so I decided to move forward and bought OWC Drive Dock USB-C Dual Drive Bay Solution, USB 3.1 Gen 2 (OWCTCDRVDCK) which works perfectly. With the new OWC Thunderbolt drive dock there are no more screen blackouts. Maybe the extra Thunderbolt adapters caused them?