I pinned down some of the watches.
Domain WRAM
SystemID GB
033B b u 0 WRAM Vert
033E b s 0 WRAM Vert Veloc
033C b u 0 WRAM Horiz
033D b s 0 WRAM Horiz Veloc
0116 b s 0 WRAM Kill Meter 1
0117 b u 0 WRAM Kill Timer 1
0136 b s 0 WRAM Kill Meter 3
0137 b u 0 WRAM Kill Timer 3
0156 b s 0 WRAM Kill Meter 5
0157 b u 0 WRAM Kill Timer 5
Spike's position (to my knowledge) is given by 033B (y pos) and 033C (x pos) and are given relative to the top left corner. As far as I've seen, Spike's velocity is either -1, 0, or 1, regardless of the direction(s) of travel, so diagonal movement costs nothing. With all that said, I haven't really looked for subpixels yet and I suspect that if they do exist they'll exist only for the nail velocities and Lore's fireballs - and they're probably more than likely not going to see use in the next wip unless they prove to be the key to the Block Swap glitch.