Any thermal paste will do, which you can get from best buy or similar.

See the second image of step 5 for where to apply it. Just screw the assembly back on after.

I couldn’t find any information on the newer models. The model numbers should be on the backside of the fans if you remove the assembly (I listed the model numbers of the fans for this one in the parts section).

Even if they aren’t the same, the merchant might still have them.

I managed to find a replacement part, see the parts section at the top of the guide :)

sorry for not getting back to you earlier, but I do not have possession of the chromebook anymore, and as such I do not know how

Sadly no, I have no idea, chromebookparts.com doesn't have a part either, haven't found one anywhere yet