No, you cannot apply XMP settings to a motherboard that doesn't support it.
No, you cannot apply XMP settings to a motherboard that doesn't support it.
Sure, you can definitely perform an XMP profile even on a non-XMP motherboard. Tools like MemTest86 can still be useful for checking system stability and memory health. Just make sure your motherboard supports XMP profiles before attempting it.
I've never come across it before, but I can assist. Just set the VCC/VCCSA to 1.1 and DRAM to 1.35, then test with 2666.