Thanks for replying. I was confused because i don't really understand how Hyper-V works. Yes you are right, single point of failure.
I had a discussion with a friend now I will share the information.
Important point, Hyper-V host will send backup files to Veeam Backup Repository via "Network". (Apply to on-host proxy method only)
Therefore using fc lun or das as backup repository does not make any difference. (VMware method has a lot of difference, this is the part i get confused.
Adding backup repository is just the same as what we have in VMware method.
Option 1 using csv is just overkill for a repository. And we don't need to go option 1, just leave hyper-v host with proxy role.
Option 2/3 is just like vmware method, can be a network share, das, iscsi, or fc (different box to avoid single point of failure)