Oh dear: you have been ignored for a long time!
Ornamental grasses can grow tall and provide some screening, and we also have a black bamboo that is big, but beware of too-vigorous bamboos that can invade.
Acers, particularly cut-leaved red acers are lovely, but slow growing, and to buy a mature one would be a fortune.
Amelanchier have good autumn colour, but are pricey as this link shows I'm afraid:
.bluebellnursery.com/catalogue/trees/Amelanchier
If the lawn is in bad condition, it could be re-made, or else give it TLC; Green Thumb, or similar organisations may be able to improve it.
You can probably dig out the pampas and laurel. Yes, rotted manure will improve the soil, or there are various bagged things like 6X, so you need a friendly farmer, or a budget garden centre.
I'll come back sometime, with ideas I have sent to others recently.