Multiple wildcard certificates for same common name on different servers

Yes, you can use two different certificate for the same common name.

We have tested many domains for the same query, and we've never found any problem on iOS devices, so 2 different domains for same domain name will work fine on iOS devices.

If you are using different certificates with different hostnames there should be no problem, even if the certificates are wild card. If you instead use different certificates with the same hostname (i.e. different IP address and server, but same hostname) you might run into problems because this setup is valid but unusual and at least security extension like Certificate Patrol will probably complain.