not sure but steeping some crystal will be a good start alot of them will contribute to head retention. Also wheat is a good additive for retention not sure if wheat extract adds the same as grain though.
DME is just LME with all the "L" removed, so in terms of head retention there's not going to be any difference. But both are better than sugar or dextrose.
If you want more head (in your beer) then adding around 300g of maltodextrin to the wort can help.