I currently don't have access to a Super UFO 8 but this is in the latest generation of backup units and I'd be pretty surprised if it didn't run DKC2 just fine so long as you have the proper header on the ROM. Same with the SWC DX2 and GDSF7, they won't work unless you've got the correct header. The important thing for the DKC series is the SRAM limit in the header.
(Don't know anything about the UFO 7 though)