I don't believe I've removed any custom events, though I did make 4 new .svg button images for the m, n and p keys, as well as all the arrow keys together. Defined them in the controller_icons.rpy as well, this is the relevant code I've added for them there:
define icn.mute = IconButton("ToggleMute", ["m", "M"], _(""), "key_m")
define icn.arrowkeys = IconButton("", ["K_LEFT", "K_RIGHT", "K_UP", "K_DOWN"], _(""), "key_arrowkeys")
define icn.n = IconButton("", ["n", "N"], _(""), "key_n")
define icn.p = IconButton("", ["p", "P"], _(""), "key_p")