The forms are normally mixed up so no I don't think it will help them - nice try though! (Isn't it year 9 they get put into 4 classes? - when 13plus boys come in - & they will be set for maths & french as well)
Yes - they do greek / german as well as latin & french until end year 9. GCSE options then start in year 10.
Do remember that they can't take greek / german at GCSE unless they have taken it in years 8 & 9 so do need to do a bit of thinking ahead
If considering Classics / MFL at 'A' level this could be an issue.
If you are good at science you tend to do better with classics than MFL - generalisation I know!