The charged ones would likely have little trouble finding their counterparts. Especially the positrons, maybe electron shells would prevent anti-protons from getting to protons.

I’m curious how stable anti-neutrons are in a matter world (and how free neutrons behave, for that matter). Does anything stop them from just joining the first atom they happen to get close enough to? And how long before they get close enough to an atom if they do, in say Earth’s atmosphere?