Yes, you should be able to do that. One comment: Queen Anne's lace, while a rather attractive plant in bloom, is hardly a desirable wildflower, at least in terms of it being on most state's invasive species list. Mind you, it's def. second or even third tier invasive, not a real problem, but generally we don't plant, nor do we need to plant Queen Anne's lace, it managing to come up all over the place pretty sell on its own.

+oM

Are you are wanting to end up with a native meadow? I ask because you mentioned 4 nonnative plants. Queen Anne's Lace is wild carrot, an introduced European weed and its not one I would choose either.

What kind of grass is it? If its a thick rhizomatous type of grass such as bermuda or one of the tall aggressive invasive types you probably won't be successful. Tall cool season grasses are often a problem in that they shade other plants in spring and the robust warm season aggressive types out compete other plants.

What kind of soil? Lavender, for example, needs loose gritty soil with good drainage.

Most times you need to do some preparation of a planting site and choose plants suited to the conditions or else amend the conditions before planting. Simply throwing out seed will not result in success. Starting new plants on a slope involves some work to get plants established, especially when there is a lot of competition of thick plant growth like some grasses have.

Poke a hole and create a hollow with a berm around the lower edge of the plant mound to hold some water back. What area of the country are you in. There are some umbel forming Queen Anne's lace native look a likes. Daucosma laciniata. Penstemon cobaea pururia would do nicely in much of the central US.

Ladybird Johnson Wildflower Center has a great service. You can ask Mr. Smarty Pants for good native substitutes for that use in your area.

Mr. Smarty Pants

They also have a area recommended species list for all areas of the US. They are not complete by any means but a good starting out point.

Recommended Species Link

Wanto makes a good point: If you like the umbel-type flowers of QA'sL (I do), there are additional members of the carrot family with similar bloom habits, but which are native plants and as such, not invasive exotics. I personally really like golden Alexanders-Zizia aurea. There are other zizias too, for different areas of the country.

+oM

I like Polytaenia nutalli. It is a yellow umbel and looks like wild parsley (an invasive) . This has A large range . Actually , even prettier is Polytaenia texana, but its range is very small.

Nuttall's Prairie Parsley

If you scratch the surface of some of the natives available on the nets, you will find many plants that will serve your purpose. It is hard to make specific species recommendation not knowing the area of the country that you are in. I have uprooted some grasses or Raked some seeds into bare spots of some natives. I bet you will get more success if you have a wetter area than me. Sometimes I have success and sometimes I don't because we will get 2 months of not a drop after the wettest spring in years. You might have to water to get them started and established.

There is probably an ironweed, liatris, penstemon, echinacea, delphinium, ratibida, blanket flower that is native to your state. A lot of those native mixes are chock full of non natives. One has to be careful and educated about what is and is not a native. I am not a purist. I just don't like the misinfo given to the un-informed. People think they are getting one thing and they are getting something totally different.