Does she really contribute more to the bottom line than any of the other 4 underpaid engineers?
And that seems like a very developer-centric viewpoint. Yes, good customer service can add a lot to a company's bottom line. Some companies have huge engineering issues and need engineers to solve them. Some companies have huge sales issues and need sales people to solve them. Some companies have huge customer service issues and need customer service agents to solve them.
I know few rigorous investors that would stand to pay their CEO/founders more than ~80k a year, at least until it's clear the company is maturing. Also, as a founder with significant equity, I'd much rather put as much of my salary that I can spare (My wife and I need to eat, pay rent, etc.) to go towards bringing in (and keeping) top sales or technical talent. If you believe in my company, the math works out very well.
I also do the occasional angel investment, and frankly, I'd be pissed to see a business I invested in run like this. Two annual international offsite trips? What?! You're building an app to schedule tweets. This is not rocket science. Get to work!
Look, not saying they can't do it.. just saying as an investor, I'd wouldn't support it. Money is after-all fungible. It doesn't matter if sales are paying for 100% of the salaries or not... if there's money being left on the table that can be reinvested into the company by either bringing in new/better talent or retaining your top talent, I would be angry. The founders already have high incentive to stay as long as they can satisfy basic needs on their salary. Employees with little equity do not unless they are paid competitively.
"Chief" and "highly compensated" are not necessarily joined at the hip. It should be possible to have a C-level exec with most of their compensation variable and dependent on company performance or certain metrics, rather than a whopping base salary.