Parsley and oregano grow like mad. So if your pot is small, they will be too big. My parsley is now the size of, say a half wine barrel and it's been cut back multiple times. Oregano is the same and I got that just as a one stem length and shoved it into the ground. You might want to just find a sunny spot in your general garden area and have them grow. We have mint growing in a small pot, but I'm not sure how healthy it will be long-term if we don't transplant it.

I've transplanted all seeds I've grown from a tin and then into the garden, no problems.

Lettuce I find grows easily, but the snails love it. Tomato is seasonal and they need something to climb on, like trellis or stakes. I'm growing capsicum at the moment, they are small plants, but the snails love them too.