If you have a Hailo-8L M.2 module you can use that on other platforms with M.2 slots.
The Raspberry Pi AI HAT+ cannot be used with other platforms because the HAT connectors are custom for the Raspberry Pi 5 unlike M.2 which is a standard.
Yes, the Hailo-8L chip can be integrated into custom PCBs. The driver and software integration is identical to systems with M.2 slots.