I wouldn't go anywhere near something that appears to have no physical address, anywhere. AFAIK, to register a company you need to provide an address to certain bodies, even if you're based on the web and draw people via a site or just through email. If you can't trace these folks to a registered company...world of nope. (Of course that in itself offers no guarantee that they're legit, but it things turn sour at least there is a place to start.)
My advice regarding any contract would be to take it to a lawyer who specializes in contract law, or contact a body such as the Society of Authors (or the equivalent wherever the writer happens to live) as they can provide advisory services. Lay it all out for them, and listen to what they say. If a lawyer is unaffordable and there's no professional advice available elsewhere, always err on the side of caution and do not sign anything that could prove to be binding.
That said, in this situation I'd already be running away so hard you wouldn't be able to see my arse for dust.