Where can I get a quick connect?

The blue cylinder and red hose use the same connectors LeLuv does. You can buy them off eBay or direct from kodidistributing (LeLuv) for about the same price.

I’ve never seen a connector like in the center picture before.

The connectors LeLuv uses are 1/8" National Pipe Thread. But all this stuff is foreign-made now, mostly in China, and a lot of Asian countries use British Standard Pipe thread. Some use metric threads.

"Standards are wonderful. There are so many to choose from!"

The Leluv’s screw hole is too big for the Size Matters cylinder’s quick release. Conversely, the first bit manages to screw it in, but I won’t force it.

The male hose fitting does not fit into the new cylinder female fitting?

For the blue one, it fits. The other one (Size Matters) the entrance is flat with 2 straight holes in it. You can click the hose in it, but there is no pin inside so the air can escape and no vacuum then.

Did you try size matters for the parts?

Yes, I did. No response yet.
Thanks all for your help. I’ll figure it out further.

Remove the two female fittings from the cylinders and take them to a hardware store. They can help you determine what the correct thread size (diameter and pitch) so you can identify exactly what you need. Many hardware stores will also carry vacuum fittings including the quick disconnect types used in vacuum pumping systems.