I am no EMC SAN expert (he is two partitions over).

You can't do a SanCopy of the live LUN, it must be off a snap. If when the SAN snap executes the VM's have not all done their own snap you will only be crash consistent.Some people create scripts to initiate snaps on the VMs on the LUN before the SAN snap, others just live with the crash consistency.

You don't need to power off all the VMs to get crash consistent. If you were to power them all off before the snap/sancopy they would all be full consistent copies.

How to achieve the best solution without spending extra budget ... um ... why don't you ask something easy like world hunger. LOL.