Just as I found with etched brass to plywood, UHU Power works very well. I've always been wary of using solvent-based glue under plastic but this stuff can be spread thinly, left for a couple of minutes to go tacky and then the sheet applied. So far, there have been no ill effects.
You'll have noticed that the bricks are dry-brush painted rather than pencil crayoned. I find this works better here as you can get in the sides around the windows and doors. As I found out when building Harper's Yard, you can't put Plastikard here, it's too thick. So paint it is.
On the roof, I've used some ScaleModelScenery slates. Draw lines 5mm apart on the roof to allow for the overlap and they are easy to line up. You are on your own staggering the joins, but it's not that hard.