No they are different.
No. You will need for professional help to replace the whole ribbon cable connector (ZIF connector).
As far as my result goes, it is preferable to choose some less watery, more firm thermal compound on both. As long as it does not run around, it is fine to use the same on both. I have not used Arctic Silver 5 so don’t know how that works. But I have used Noctua NT-H1 and Thermal Grizzly Kryonaut, both working well. I’ve tried something quite watery from Prolimatech which quickly stopped working after like a week.