Yes, the M.2 slot is compatible with this motherboard.
Yes, the M.2 slot is compatible with this motherboard.
It's a M.2 SATA SSD, which means it should fit in one of the M.2 slots on the motherboard. Be aware that you're restricted to SATA III speed, so it won't be as quick as an M.2 NVMe drive. If you're purchasing this used, I wouldn't suggest an i3-6300 these days.
It functions because the M.2 SATA isn't compatible with PCIe SATA.