I just looked on the OhBaby 'starting solids' section quickly and it said to start introducing meat after 6 months so theoretically it should be fine.
But take note of this reaction and maybe hold off on more meat for a few days and see if he is still unsettled and if not, try again and if he is a grump then maybe leave meat for a month or so.
I'm sure that was just reiterating what you already know

so I'm not much help but good luck!
ETA - I'd have thought the other foods you mentioned should be fine for his age. Someone correct me if I am wrong!

Edited by nikkiwhyte