On the Grand Alliance Forums, user75hastings69 (who seems to be THE Hastings from Warseer) shared the following as stuff he heard about for
TOW.
Updated Mighty Fortress? Yes please!!
https://www.tga.community/forums/topic/22826-the-rumour-thread/?page=8383
New Chaos Champion Plastic
New Chaos Knights plastic
Expect updated core kits around summer (I asked if Orc boyz would be included and didn't get an answer, so I have no idea what these might be)
New Orc Rock Lobba (this might not be WHToW though maybe AoS as the description reminded me very much of the old Man Mangler kit - so maybe it's for AoS Kruleboys or something as they have learing face shields)
Seige Supplement
Chaos War Mammoth
Updated Mighty Fortress
Kislev army launch around the time of seige book.