If we have multi already I'd just replace multi with ocellatus since they are basically the same thing. Dwarf chain loach is a good choice and so are microctenopoma ansorgii and apistogramma borreli (pick 2) apisto may be larger than 2" thoughSo Ocellatus and a small species of loach such as dwarf chain loach
shell dwellers are already takeSo Ocellatus and a small species of loach such as dwarf chain loach