They should be just fine together, especially for the first couple of weeks. Just keep an eye on the standard chicks to make sure they don't hurt the smaller chicks. I've raised standards and bantams together, though, and generally didn't have an issue. Once the standards start their growth spurt and get quite a bit bigger than the bantams, you might want to separate them until they're adults, though, just so the bantams don't get squished. That said, as adults bantams and standards do fine together.
Basically, yes, you can raise them together, but just use your judgment when it comes to size differences and keep an eye on everyone just in case.