storage - SAN connected through SAS with SATA disk

let's have P2000 G3 with SAS Dual Controller and DL120 G6 with HP SCO3e SAS HBA cards.

1) I know it's bit dumb question, but just to be sure. The array will be filled by SATA disks. Will be the SAS connection to the host degraded to SATA performance ? I hope not ..
2) Does SAS support multipathing ? (XenServer)

Thanks.