I don't know if you can open a full AC14 file in Start Edition but the setup is not feasible because just think of all the model data you would lose.
Even if you can open the full AC14 file, all slanted and profiled walls/beams/columns would be gone, curtain walls would be gone, hotlinks would be gone etc.
So it just wouldn't work.
If you want to work for someone with a AC14 full licence, you will have to have a full AC14 licence too.
Actually, I think it even says in the promo material that Start Edition is meant for one-man shops.
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