Europa is a fully bilingual school, so children are streamed into either (IIRC) french or german groups and taught that language in all subjects throughout school. It's fab if that's what you want, but it's fairly niche if you are not interested so much in dual-language teaching.
Don't know about the others, but they are all based in nice villages, so that's a good start!
We're also moving to the area and my son is entering year 1 in Sept. I'd agree that many of these schools are likely full. I spoke with Clifton Hampden last week and they expect to be full in all year groups, unless someone leaves the school. I've found the best way to find out if there are spaces is to call the schools directly.
Sutton Courtenay school has a different profile from most village schools in that it has an above average number of disadvantaged children.It seems to be regarded as the school for the council estate rather than the whole village. Have you thought of looking at the primary schools in Didcot itself? The schools you have mentioned are all very small and finding spaces in them could be an issue.
On the positive side my DD goes to Didcot Girls -your catchment secondary and I have been hugely impressed with it. That probably seems a long way off though.