It's not been mentioned here, yet, so I'll also throw this into the pot:
In Rev.7:4 he hears the symbolic number.
In Rev.7:9 he sees them as a great multitude
In Rev.7:14, 15 he finds out that this multitude are priests in the temple, with the one on the throne dwelling among them (which is either the lamb or God or both).
The WTS doctrine is screwed, when you read the whole chapter, because they believe that only the 144k are priests. That could only be the case if they are also the Great Crowd.
Alternatively they are Israelites, and the Great Crowd are the Priests, who dwell with the lamb (and I don't think they would like to put it that way, either, since they want to be kings and priests).
The Christian view is that the number represents all Born-Again believers (simply, Christians). They are apportioned places in the promised land (being heavenly places).