We live in Lavant and my DDs went to the primary school there. It's beautiful but you do really pay for location.
Bishop Luffa is a good secondary, but you need to do church. Also, be aware that although their results look stunning, they have very "thinking" parents, the type who don't mind doing church every Sunday for 2 years to get their child in. These same parents pay for a lot of extra tuition. I tutor maths and most of my pupils come from Luffa. DD2 just did a year 6th form there and she reckoned about 3/4 of the class were quietly paying for outside tutors. I'd still recommend it, however, it's a lovely school - but take the results with a small pinch of salt. At 6th form level I'd go for Chichester College of Technology over and above the schools. Midhurst Rother College is very up and coming - my goddaughter goes there and quite a few other Lavant children and I've heard very good things about it.
Traffic south of the bypass (A27) can be horrendous. My sister used to live in Pagham by the sea which is lovely, however, she had to leave pretty early to work so as not to get caught in the traffic. For this reason we like north of Chichester despite being further to the sea.
We used to live near Arundel/ Littlehampton, cheaper, and a bit less stuffy, but schools not so good. I do miss it a bit as we used to go to the beach much more.
Of the villages you've listed I'd go for Bosham over the others due to ease of getting to and from it. Have you looked at Westbourne if you're looking in that direction?
lilypoppet you should pm me!