Terminal vs Shell vs Processes on ARM (Apple Silicon)

How does Big Sur and ARM (Apple) silicon handle the following permutations? Say I run Terminal as x86_64 using Rosetta2, then does that mean I *must* use a x86_64 shell? If indeed I use an x86_64 shell, can it only execute x86_64 processes or Universal bins? Similarly, if I use a native Apple Silicon Terminal, does it mean I must run an ARM shell? I hope what I'm asking makes sense. I ask as really what I'd like to do is use Home-brew a certain way. I want to use an ARM version of iTerm2 (Universal binary), then run latest ZSH (may be x86_64 depending on what version brew installs, then also use a mix of ARM and Intel binaries.