mugshot VS FreeIPA

As the mugshot package is not in the Fedora repositories, how can a user picture be loaded so it displays in the whisker menu and logon screen in XFCE 4.16?

Try setting your distfile URL to https://github.com/bluesabre/mugshot/archive/refs/tags/${pkgname}-${version}.tar.gz, then regenerate the checksum using xgensum. You'll also want to set homepage to the project's GitHub URL since it doesn't seem to be updated on launchpad anymore, and add the following line to your template if you haven't already: wrksrc="${pkgname}-${pkgname}-${version}". Finally, you may want to consider changing the maintainer field to have your information since the current one obviously hasn't cared enough to update the package in two years.

I also want to try FreeIPA but as it's built on top of 389ds I'm afraid that it's gonna be as big of a memory hog (will try it later anyways) and has many things I don't and won't need, which I'm afraid would add complexity to setup.

FreeIPA server and replicas

A good place to start might be FreeIPA.

FreeIPA1 is not written in PHP. I believe you are confusing it with another project, maybe FreePBX which is written in PHP?

I had Fedora 34 installed to an SD card for a FreeIPA node which worked well. It was most likely an earlier release (32 or 33) running on a Pi 3B which would occasionally run out of memory, so the whole thing got transplanted to a Pi 4 with 4GB. I'm pretty sure I used the disk image to install since I like to start from a minimal image and only install what I need.

Take a look at FreeIPA

https://www.freeipa.org/page/Main_Page and https://github.com/freeipa/freeipa/tree/master/doc/workshop