Should I include my specialty grains in a mini-mash?

Flaked oats, like quaker oats, have been pregelatinized so you can mash them directly. Malted or not has nothing to do with it. Irish oats or steel cut need to under go a gelatinization process, via cooking them. This makes the starches accessable to the mashing process.

You can add your specialty grains if you don't have space limitations in your mini-mash tun. Otherwise you can just steep them in your brewing water while the mash happens.

I used to set up my mini-mash, then I'd get the water heating in my brewkettle and steep my grains while it heated. After steeping, I'd start adding my extracts and get the boil going. Right about then the mash would be done and I'd sparge that into the brew pot too.

Doing it this way of course, I was doing full volume boils however. If you're mini mashing and doing partial boils that may not be feasable.

If you're using flaked oats you can add the steeping grains to the mini mash and save yourself some time. If the oats are un-malted you need to do a cereal mash to gel the oats and release their starches.