User blog comment:Kogath/Monster Hunter X Discussion/@comment-3298463-20151126184513/@comment-3298463-20151126203725

They just haven't appeared anywhere, and some people are already up to Shogun Ceanataur... so if they were in, they probably should've shown up for now. They're not exactly deconfirmed, but at this point I find it very unlikely that they're in (especially Great Jaggi, which should be one of the very first monsters, unless they've made it

Also there's supposedly a complete list of monsters floating around (made by the same guy that posted the Shagaru tweet) and neither GJ nor Giadrome are in it. So far, it seems to be accurate (it predicted the HC Lagombi, and also the new monster's name. According to it, Akantor, Ukanlos, Alatreon and HC Garuga and Uragaan are also in. It's not a confirmation but I think it's probably correct)