hidmacros.eu

No Fn key is hardware thing, not able to send from windows (AFAIK)
Edit: But you might be able to send appropriate virtual key with lmc_send_input, the code should be VK_MEDIA_PLAY_PAUSE

No

Almost dead.
It's not clear to me from your description what you're trying to achieve.
In general for such fine tuning I recommend use lmc_send_input over lmc_send_keys. Send keys may have bugs and you have more control with send input (down/up calls, keys with flags etc).

No, mouse clicks are not supported in luamacros

Don't handle whole keyboard, just one key - https://github.com/me2d13/luamacros/wiki/Triggers

No, see https://github.com/me2d13/luamacros/wik ... -keyboards

Unfortunately not. Hidmacros can't "hook" only one keyboard

You don't have to use string.byte. Just use the number itself in condition - the one being printed as not assigned.

ad {+}: In Hidmacros? Do not expect any fix there. In luamacros you can use workaround with lmc_send_input
ad layout switch: be more specific. Yes, mapping is related to character being sent, not to physical keyboard key

Blocking the original keypress is basically a hack, some applications still can recognize it. Maybe Blender is one of these apps.