From the information that Despair gives regarding the 'sighters' contained in the 1891 Census it looks as though the location of Ty'n Y Pwll Bach, and Ty'n Y Pwll is in the area where the shop and Ty'n Y Gongl Farm are located. There are quite a few places shown here, huddled together and, due to lack of space, will not have been named on the map.
Regards from Sweden.
PS My GGG grandfather was from Plas Llanfair methafarn eithaf.