It makes sense that the first marketing hire on a product-led organization is the Product Marketing lead :). I would say put your strategy together and depending on the priorities you will see what kind of marketing hires you need, vs perhaps going with external agencies for some marketing activities. You may want to keep the strategic items in-house like competitive intelligence, but anything related to marketing campaigns you could start with external agencies / contractors with the optionf or them to become full-time. It really depends on your audience and what you are trying to do next. For example, if you are targeting developers, my first hire there was a technical writer to clean up the product / API / SDK documentation. So sorry to say that the answer here is "it depends", but hopefully the context above can provide some pointers.