I have grown apples Winter Gem and Cox Queen, on M26 rootstock and have done well with them. You may want to get them on M27 rootstock which is more dwarfing. Mine were grown as espaliers, trained along a post and wire system. This consists of stout 3 inch square posts about 8 ft apart, with 3 wires running between the posts, kept tight with straining bolts.
It's a bit diificult to train apples in a fan shape I think - folks tend to do fans with peach and cherry, normally up against a wall.
You say you want to hide your compost bins, another thing to bear in mind is that when the trees lose their leaves in winter there won't be much cover.
