[kylebrown]

I'm a programmer that does more front-end (html5/js) than back-end, and perhaps 'adequate' design skills (I don't do graphics, but can make decent-looking prototypes with enough css).

When looking at the description for the designer job in the OP, its not the design/technical combination that seems over-the-top, but those two jobs and a third job doing A/B and conversion rate testing. That needs to be delegated to somebody else, either a separate designer, a Quality-Assurance person, or the project lead.