New does not guarantee heap allocation and simply avoiding new does not guarantee stack allocation. New is always used to allocate dynamic memory, which then has to be freed. By doing the first option, that memory will be automagically freed when scope is lost.
I'd definitely try XOutput first before anything else. Just keep in mind to not map your N64 buttons to Left/Right triggers. Rogue Squadron doesn't recognize analog triggers as buttons and will ignore them completely. Instead, if you need to, map the buttons to L3 and R3, listed in XOutput as LTB and RTB.