once you've primed them, you can use any finish you like, another alternative is chalk paint. I have made my own in the past and it works. Pinterest has some good hacks.

We do have a sofa bed from Ikea which we bought second hand BUT, for extra guests there are deep blow up beds that are self inflating (so no spending an hour pumping it up!) AND, we bought a thick mattress topper to keep under our own mattress that we can pull out when needed to go onto the blow up. Comfy as a normal bed then but doesn’t take up any space

The door handle is in the same position as yours, in the upper centre of the door. There is no room for door hinges, but even if there was room I still want the door to pull out like a drawer rather than swing open so that there is immediate access to the contents of the attached drawer. I know it would have to be the bottom drawer. If you have any suggestions as to the best way to attach it that would be great.

We've got the high back soderhamn which is discontinued so went with bemz. We absolutely love them and didn't take too long for delivery. I think we got the samples free at the time.  They have so much choice and really good quality, better than our original IKEA covers. They have different types of material to suit your budget.