These screws are labeled as “M2x5”. I don’t think they’re 2.5mm, they appear to be the same as the 4 screws that hold the palmrest to the bottom shell in step 15.
Note that there are 4 flat “grabbers” that attach to flared posts on the back of the keyboard, so even when the 5 tabs are released, there will be some resistance, and you need to pull the keyboard straight away from the housing with a little force to release them.