Natembeya I doubt will decamp. RiggyG has been propping him - which indicates his bg checks are not suspect. Doesn't need kalenjin either - he beat Chris Wamalwa flat despite the FordK-UDA zoning in 2022. Bukusu plus kikuyu is quite enough.
Matiang'i is different as Uhuru protege. No money nor machinery (nor brain!

) of his own. Could easily join Raila if Uhuru wants it. Or well rebel and stick to united opposition. ODM is definitely more popular and easier to join/sell than UDA in Gusii. In Jubilee I think Kioni has already rebelled against Uhuru and is singing #Wantam. RiggyG has promised him a CS post. If Matiang'i stops tagging #Wantam brigade we'll know his true colors.
Another suspect is JB Muturi - could easily be Ruto/Uhuru decoy. Just like 2022. His strange abrupt turn against Ruto was suspect.
Both camps have foxy brains - RiggyG, Ruto - so expect such tricks, twists and turns. Most Gema in UDA will dump Ruto but are lying low for now.
Basically if you see RiggyG propping someone - like Kalonzo for PORK or Matiang'i-Natembeya for DPORK - it means RiggyG has 411 Ruto has dangled some cash. The polls or leaked lineups make the ground hostile to joing Ruto.