Are they less likely to get bullied at private?
No, bullying happens in both sectors. Some schools are better at dealing with it than others, regardless of whether or not they are fee-paying.
Less likely to fall in with a 'bad crowd?'
No, this could happen in either sector. Privately educated children are not necessarily angels.
Less likely to have to deal with really disruptive behaviour in class?
Perhaps. It's probably easier for private schools to exclude the most disruptive kids, but this won't be an issue at all state schools anyway. Low level disruption exists in both sectors.
More likely to be motivated to try their best academically?
No. Motivation comes from within, and can be encouraged by supportive parents. However, a child lacking in motivation would probably get pushed more in the private sector.
More likely to be challenged (for very able DC)
Not necessarily - it totally depends on the school. Our experience in the state sector has been very positive.
and less likely to be 'overlooked' (for less able DC)?
Maybe. Some quiet, academically average kids might well benefit from the extra attention and smaller class sizes.
More likely to have exposure to high quality music and music-making at private?
Possibly, yes, depending on the school. However, these opportunities can be pursued outside school if desired. Children who are exceptionally talented will probably need to go outside school in any case.
On the other side, are they more likely to feel very under pressure at the selective private school?
Possibly, yes, but it depends on the school.
Less likely to develop the ability to relate to people from all different backgrounds?
Possibly, yes, but depends on many other variables.