More chickens!

Hi i am after a bit of advice! I have 9 chickens currently: 1x pekin bantams, 2x standard polish, 2x appenzeller, 2x padovana, 2x silkies.

I would like to expand my flock and get large breeds (for bigger eggs) as well as a frizzle. I would like more variety of colours in eggs as currently all mine lay white/cream eggs!

1. Are the large breeds i introduce likely to get along with my bantams?

2. What breeds would you suggest? I am mainly looking for brown and green eggs.

I am currently looking at: Ameraucana, orpingingtons, faverolles, cochins and welsummers...

I am as about far south as you can get in the UK so cold is not a problem, they have a whole field to free roam, a 36m2 secure run and a 6x4ft shed kitted out with 3 different height perch bars.

Thank you for your help!