I would plant rosemary in its own pot. It is a perenial and requires different care. So goes for the thyme. I think a 2 gallon pot for each should be a good start. You can always upgrade the pot size the following years if necessary.
You can plant Basil, dill and parsley together. They require similar watering, fertilizing care. But then the question is how much of each do you intend to plant. Some basils can grow real big and may need a lot of space. So if you have something like a window box, it should be fine then.

I personally plant parsley and dills in clumps. There can be one per 2 square inch. You can always thin them.

Every time I've tried to grow herbs together in the same pot, none of them has done well. They all have different germination and growth rates, so growing them from seed together is not a good idea. Dill, parsley and rosemary need deeper pots. Two gallons would be better for all of them, but you could do the thyme and basil in one gallon pots if you have only one plant per pot. Parsley produces a large root mass and is a bit of a bully once it gets going. Dill doesn't like root disturbance and so should not be transplanted. They all need sun, but grow to different heights and widths, so some will shade the others in the same pot. Parsley and basil need a lot of water, but thyme and rosemary need to dry out between waterings. Dill needs staking in many cases.

Sey and Ohio have it right. Conventional wisdom and misleading advertising will have you thinking that you can grow all types of herbs together into your own little "garden of eden" container on your window sill. It's a huge myth and just doesn't work for the reasons explained above.

If you have a yard, find sunny spots to plant the rosemary and thyme in gravelly loose soil. They are Mediterranean perennials that do fine even in my searing Vegas heat with once/week watering. The flowers aren't much to speak of, but they're not grown for that. The shrubs themselves look handsome in the landscape though and you won't help but brush the leaves with your palms and smell them every time you walk by.

Thanks for the advice, it is very helpful. I really thought it would probably be okay to plant herbs together, but I guess not. Good to know!