In that case, I'd recommend prioritizing Instagram since content there is very lifestyle- and aesthetic-oriented. Snapchat would be great for showcasing personality but if you don't have the time, Instagram Stories should function similarly for you.
Facebook has largely become pay-to-post. It's unlikely you'll reach your audience unless you do some paid campaigns, and it will continue to grow in that direction as 2017 moves forward (random fact: they're predicted to run out of ad inventory by the middle of this year). I would only recommend being on that platform if and when you have a solid conversion point (i.e. a product/service to sell).
Whether a blog is necessary or not depends on what you're trying to do with your overall strategy. Perhaps if you share some of your content goals and some details about your blog (e.g. where it's hosted, what you've been doing with it, etc.), I could give some advice on how important it is and whether you can leverage it somehow.