As kriss has already stated, Matthew 11:14 documents that IF John had been received, he would have been it. HOWEVER, his head ended up literally on a platter.Malachi 4:5
Behold, I will send you Elijah the prophet before the coming of the great and dreadful day of the LORD:
It's not in the spirit of, it's Elijah himself, just as he appeared at the transfiguration. There are your two witnesses, in my belief. However, one certainly cannot remove Enoch, and I will admit that it is not entirely clear. However, having studied this on numerous occasions, I don't think you can make the two witnesses a body, church, or office.Zechariah 4:14
Then said he, These are the two anointed ones, that stand by the Lord of the whole earth.
As kriss has also pointed out, they are separate from the seven candlesticks, therefore they obviously cannot be a church.Zechariah 14:2-3
And said unto me, What seest thou? And I said, I have looked, and behold a candlestick all of gold, with a bowl upon the top of it, and his seven lamps thereon, and seven pipes to the seven lamps, which are upon the top thereof: And two olive trees by it, one upon the right side of the bowl, and the other upon the left side thereof.