Its actually quite easy. Just start AnimalMap 1.5, load your save file and click on "Edit Neighbors". There you can change any neighbor you don't like with the monkey of your choice. Click on "change" and then choose the name of a monkey (Boone, Cesar, Peewee). Maybe you should change the personality and catchphrase too. Here is the info for it:
click me
Finally press 2 times "done" and "Final Save". This should work (haven't tried).