Q: are RAM modules replacable?
A: yes.
Q: is the SSD replacable?
A: yes.
Q: is the WiFi/Bluetooth module replacable?
A: yes.
Q: is the processor replacable?
A: yes.
Update: it appears that we have two different logicboards. Mine (internal one) includes sockets for RAM, CPU, SSD and WiFi/Bluetooth modules but end-user hardware not!
P.s. I will no longer be able to comment on the matter (I am a software engineer. Not a hardware engineer).