Dear Snowdrop,
Iffley village is lovely. We sometimes wander in that direction, or go to Iffley lock to feel a bit like we're in the countryside.
I don't know anyone who lives there so I can't say anything about the demographic or community. There are a couple of nice pubs though, so perhaps if you're up here looking at houses you could try and find out a bit more. I seem to remember that there's a community run post office - a pretty good sign!
The great thing about Iffley village is that you can easily walk to east Oxford. You're also close to Donnington doorstep which is a fabulous independently run (but charitably funded) family centre. There'e a lovely atmosphere at DD and they serve really good food. I know that there are quite a few families living in narrowboats not far from Donnington bridge and East Oxford is brimming with young families.
The Isis pub on the river is a nice place to hang out in the summer. They also serve great food and do afternoon teas. You could walk into town along the river in half an hour, and you can easily get to loads of activities for you and your LO in East Oxford.
Rose Hill is a deprived area and this is probably reflected in the school. I think the nearest alternative would be Larkrise which seems to be doing well. You could also think about Hinksey or St Ebbes. All Oxford schools are over-subscribed at the moment but I know people who have got into schools from out of catchment. Places come up as there are many academics who come and go with their families.
Oxford montessori schools, who run the montessori at Iffley, have a good reputation. I know someone who sent her children to the one at Wolvercote and really liked it.
I hope this helps. Good luck with your house search!