We found a local "mattress manufacturer" via the Mattress Underground forums.
This place actually assembles the various layers on the bed: spring coils, foam, latex, memory foam, wool padding, etc., and then stitch them up in an enclosure so it looks just like a regular Queen size mattress.
We went to the factory, and they laid out the layers until we each had the feel that we wanted. I'm a side sleeper with neck issues; given the hip and shoulder pressure points, I wanted softer than DH. I also run colder at night. DH wanted firmer, and he likes colder at night.
So I ended up with memory foam on the top layer, with latex underneath it. DH had no memory foam. They have a 90 day "edit" feature, where they will actually come to the house and swap out layers if you get it wrong - which requires unstitching the mattress cover, and then restitching on site. They tell us that the most common error is clients thinking they want a firmer mattress than is comfortable, so they edit to make it softer after a month or so.
In terms of bedding - I use the blanket, DH kicks it off. And we installed a ceiling fan in the bedroom, so we can keep the AC at a reasonable temp, but the fan makes it feel cooler in the bedroom.