Arguably the only crawler that really matters is GoogleBot, and that renders javascript apps nicely these days. Not much you need to do in terms of Meteor, although setting the page title and meta tags via javascript when you navigate to a new page will help get those bits right.
I don’t really get what backlinks has to do with Meteor, backlinks are links on other sites that link to yours.
Just like @juliancwirko said, I had problems too using dfischer:prerenderio package, so instead I picked the npm version (prerender-node).
For SEO purposes, I use Dochead (for Meta tags) along with prerender (in order to make my content crawlable by Google bots and other crawlers), and I am pretty happy with it !
Good point. This is presumably if you want different social media images per url? Otherwise you can just set the fb meta tags in the head and facebook will parse that for thumbnails and description.