Question regarding VMware Oracle RAC cluster and Avamar backup

I am in the position of OS systems administrator and am setting up our first VMware based Oracle RAC cluster.  We are a fairly new Avamar user.  The Oracle data disks are VMDKs with multi-writer enabled.  Oracle ASM is managing the space on the raw partitions.  The DBAs currently backup the Oracle DBs via their own RMAN scripts. 
1. Can we backup the base OS VMDK while bypassing the Oracle data VMDKs using image mode backup?

2. If we need to load the standard Avamar client to backup the OS filesystems, will I also have to install the Oracle Plug-in, even though the DBAs still want to use their current process to backup the DBs?