First though, I like it!
Unfortunately, subsequent thoughts that pop into my mind are reasons I don’t think it will work… 
Including what seems to be a dealbreaker. There are tracks that take up the space under where it seems you placed the arrow keys.
Nrp said the trackpad module uses a “different interface”.
From something said elsewhere I suspect it might be i2c instead of usb. If this is the case, it could make custom modules for the Touchpad area no longer straight forward.
You might feel it works fine & is worth the risk of breakage, but I wouldn’t expect Framework to agree. You might have had good luck, perhaps skill, in removing laptop keys without damage, but others aren’t so lucky. If I recall, one person who did it on the Framework-13 to create a mixture of transparent & non-transparent keys mentioned breaking a few in the process.