From the options you mentioned, option 2 is what I would do in your case. There's no real drawback in using an RDM, you basically present a LUN to the ESXi host and attach it as an RDM to a VM (no SAN tools or management required). The only thing you cannot do with an RDM in physical (pass-trough) mode is to take VM snapshots, so you'd need to use a guest OS agent based backup tool.
André