2.The context of John 10:16 reads:' "And I have other sheep, which are not of this fold; those also I must bring, and they will become one flock,one shepherd.' Compare it with Ephesians 3:6 which reads:' that people of the nations should be joint heirs and fellow members of the body and partakers with us of the promise in union with Christ Jesus through the good news.'
At John 10:16, Jesus was speaking to his Jewish listners(who are in this fold) that there are also others who are not in this fold(non-jews) that he must bring and they(both jews and non jews, that is gentiles)will become one flock.
Interestingly, Ephesians 3:6 renders that 'people of the nations(gentiles) should be joint heirs and fellow members of the body[therefore become one flock] and partakers ......in union with Christ..
Even more interestingly, last week Watchtower Study article( w1/15, 2012, study during week of March 26-April 1, ph 13 on page 29) explains,
'Those invited to be in the new covenant were alsoto be anointed with holy spirit.(2 Cor. 1:21) Faithful Jewsand then, Gentiles were included.(Eph. 3:5,6).(bold and underline mine)[ironically the WT contracditing itself unwittingly, I believe this same study article will provide at least half of your questions. But make sure read cited scriptures and their context. I love it when the WT studied for you and only to support opponants' points. The WT study articles, to me, have proved to be the best source of discrediting its own doctrins]
Now we can easily draw the answers of the First and Second questions,
1. who the 'other sheep' are: Gentiles
2.the context of John 10:16: the blessings of the Christ' good news will be extended to ' people of the nations(gentiles).' No where these scriptures are pointing 2 different callings, namly, one, havenly and the other, earthly. It's only happening if someone decideds to interprit it to fit his/hers own understanding.