As mentioned, the two GC titles were small, and fitting all three games on one dual layer Wii disc should be easy...however, IGN did make mention in their preview of one thing in part 2 which does sound a bit over-compressed:

"Metroid Prime 2: Echoes is equally fantastic with Wii remote controls and the updated widescreen, 480p visuals, but the GameCube game used a bit more FMV – on the Wii, the compression is a little, shall we say, bleah during these cutscenes. But when it jumps back to realtime in-engine, everything flows sharp and smooth."

Nobody is going to play Echoes anyway.

MadWorld
House of the Dead Overkill
Metroid
Resident Evil 4