There aren't many small cases that offer external drive slots for your blu-ray drive, would you be okay with moving the blu-ray drive to a USB-enclosure? If the drive has to be in the case, then maybe a Fractal Design Core 500 would be a good option.
Mainboard is going to be more tricky, socket 1150 boards are very outdated, you will have to look on the used market for those. And most likely there won't be many ITX boards available on the used market, those weren't really a thing back when socket 1150 was available. So an upgrade might be the better option here. Maybe something like this: https://uk.pcpartpicker.com/list/xXJypH