You know, it's funny. I'm older, and I read this like "new company, some money, maybe a prototype...it's wide open to be conquered. OP could be the CTO within a year.

I believe they need a technical project manager and an operations manager - not a PHP dev.

Check.

Looks like the focus is blinkered on 'delivery' but not on what is being delivered, or why they need to deliver it, or evaluating how they work.

This isn't the time for cybernetics. Business people need a business to do at the stock market [meetings and networking events], so delivery is a big part of having something to sell.

At a guess requirements for the project were not properly captured, I doubt focus groups or surveys were done either,

This is off the deep end when talking about startups.

Employees needlessly working serious overtime because of lack of project management. Not sure how much pressure direct or indirect there was to do this.

See above, someone probably just needs to step up. They're probably thirsty for someone to apply some structure like you describe them needing here.

Will this be a problem if them being absent is a regular occurence and we need them to make a call on something.

Startup CEOs are always in and out because they have to do their thing. I'm not sure what you would rather them do, yak away on a phone all day three tables away? PROTIP (Source: experience): CEOs often aren't interested in the PRO-CON about some technical thing (you are a PHP dev after all) as we creative coder types are, so just make decisions. Let them learn to trust you by trusting yourself.

That said, if you don't believe in the product, you don't believe in it and that should carry a lot of weight. However, as a technical person I have found myself surprised at what is actually viable once you launch on the Internet. I just don't have the business focus to see it up front. That's OK, it's biz ppl's jobs to know that stuff.