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You're missing some key positionals to really build a well-rounded team, but there is nothing stopping you from using a lineman as one of those positionals until GW actually makes the minis you need. Just make sure you mark them to show who's who and that your opponent is fine with this. I use these rubber bands to help denote which linemen are Black Orcs and which are Blitzers, for example: https://www.amazon.com/gp/product/B00E7TKSWK/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

EDIT: I forgot to add that by doing this, you absolutely have two competitive teams right out of the box.