You have it kind of backwards. Not these sites or their certificates are vulnerable, but the certificate signing process itself is. And by extension all browsers that accept SHA1 certificates anywhere are. To clarify, what the attack does is generate two certificates that have the same SHA1 hash, one of them legitimate and one of them illegitimate. In the worst case scenario the illegitimate one is an itself an intermediate CA, which means the illegitimate one can MITM any connection. You send the legitimate one to the CA to get it signed. When you get it back you swap the legitimate certificate with the illegitimate one - which is possible as both have the same hash - and voila, you have broken TLS world wide.

Having a certificate with SHA2 will not save you. A client under attack will not even see it. The only thing that helps is stop accepting SHA1 certificates (and especially SHA1 intermediate CAs) globally. All this stuff about accepting short lived certificates is only a publicity stunt by Google to raise awareness about the issue (an attacker can forge a certificate with any expiry time she wishes).