<p>What would be their roles?</p>
<p>This is a broad question.
It depends on what kind of engineering and the products the company develop.
In a biomedial company, EE, ME, BioE, software E develop medical devices, instruments,…
In food industry, ChemE design food packing process,…</p>
<p>The role could be design and development engineer, R&D engineer, test engineer, production engineer, sale and marketing engineeer, managers,… or even president if the the engineer founded the company.</p>