Advice on planting a magnolia (or something else?) for screening
A sorbus (rowan) might work well. Flowers in spring and berries in autumn, and nice delicate-looking foliage in between. There are lots of varieties with different coloured berries.
A magnolia has quite a sprawling habit, they look great, but will get in the way until they get tall enough. Well that's my experience with them!
Planting close to boundaries is a real pain when your neighbours decide to severe limbs.
I've a small apple tree, it's great, it produces fruit, but I can't get under it. It's a bit of an exclusion zone! Which is fine, and probably goes without saying, but be prepared to not be able to use that part of the garden until the tree is tall enough.