No. WSL is a part of the NT kernel (part of their modular architecture, quite cool to read about) and can't be replicated with an alternative program loader like Wine. You'd need to run a whole new copy of the kernel to get a second instance of WSL, which can already be done through virtualization.

Nope. WSL is basically a reimplementation of the Linux kernel's syscall layer (or at least the original version of it was - WSL 2 is an actual Linux kernel running in a VM). If you do a Linux syscall from within a Wine app it calls into the actual underlying Linux kernel and Wine itself makes heavy use of this within its libraries. WSL on Wine isn't possible and doesn't really make sense. I guess it might be possible to add support for WSL 2 since that's just a VM, but I'm not sure why you'd ever want to since it is just a VM.

Maybe by using qemu? (Windows on qemu on Wine on Linux on Windows)