Unfortunately, this doesn't mean its actually "open". It means they're open to accepting your applications and it looks like they'll be adding people in quicker than before during the beta.
Yes-ish. If it takes too much of your time to produce anything that looks/feel reasonable, then hire one. If you think you can get by doing it yourself, then make it so. If you have enough chops to get by, but don't know where to start, yes - then start tweeking stuff yourself.
try to stick to something simple and clear that lets users know what they're doing next.