execute command / Problem

I am trying to make a mob kinda like a sheep and seen I cannot despawn a mob so I figure ill despawn it myself with command tp @e[type=endercave:wisprabbit,r=1] ~ -1 ~

I try it with the / and with out /

not sure why command isnt doing anything. the mob that is suppose to replace it know rapidly spawns do it not dying or despawning or tping away. I would like to replace the wisprabbit and replace it with the hairless one.

I know I can fix the rapid speed spawning but not sure how to replace the main one with out killing it well that can be seen. the only other thing I can think of is adding a potion effect on rabbit and then kill it and hope I can not see the death of the corps.