Glad you like it and appreciate your suggestion!
Yes, Pi, Arch and Rust are awesome!

1. I did not time the compilation. Likely half to one hour. Not bad.
2. Arch was chosen based on following reasons: It has a mature 64bit support, so Node can be natively compiled. I suppose CPU is more efficient and Node can run on 64bit. It makes use of the full potential of a $35 board. It has a wider range of packages (except some proprietary ones). Highly customizable, for example, the 53 port problem can be solved with a command. Lighter weight, unnecessary packages are not installed by default. Arch is probably the best choice to dive deep into Linux.
3. I tried Rust nightly channel. It’s not stable. It produces different result every night. 😂 Sometimes it passes, sometimes not. The stable version caused the +fp warning, so I switched to an earlier version. The stable version actually compiled a working Node, so I suppose +fb is not a big issue.
4. Cross compilation works. I’ve done it a week ago, but haven’t included in my guide. The guide was aimed to raise interest of Pi, Arch, Rust and Sub. Cross compilation is not suitable in the initial introductory guide. People were eager to know how well Node is supported on Pi, and I proved that it can already be compiled natively and run on Pi 3B. I will include cross compilation in my next guide about Pi Zero. YES, Node runs on the $5 Pi Zero W.
   Cheers!