No deli meats like ham and devon?
You CAN have them, if you get them sliced fresh.

Can I eat feta? As long as it isnt full goats milk?
YES - you can eat ALL cheeses in Australia as they are pastuerised, however, you may wish to steer clear of any SOFT (Camabert, Brie) cheese if you like as they are highER risk.

Can i eat swiss and jarlsberg cheese?
Of course yes.

Can I eat tuna? like the tuna mixed with onion and tomato?
Yes you can, but you will need to limit your intake of mercury-heavy fish (Oily fish, like tuna, mackeral, tuna, sardines, etc)

You can eat ham from a packet, personally though I would rather get it fresh sliced from the Deli than pre-sliced in a factory.

All the best