Replication is my goal

I have built my first server, and server 2012r2 is running with 2 arrays and a hyper-v vm configured. My 5 year old adequate production server has ESXi and 2008 r2 with beaucoup licenses for 5 different databases and 20 staff. Now I have some software issues with virtualization for replication.

Moving a virtual machine to a newer server sounds simple, but with switching esxi to hyperv and upgrading 2008r2 to 2012r2, it seems daunting. Any advice on converting an esxi vm to a hyperv vm? I assume I would upgrade the old server and vm 2008 to 2012, make a hyperv vm there similar to the new server, do the conversion from esxi there, then replicate to the new server, and then switch primary and secondary roles

Both servers are similar with a small fast array and a large slow array. I am anticipating converting 2 esxi to vhdx files, one for the OS and database programs of 300 gb and the other about 1 tb of documents we need to review occasionally.  I don't understand the mechanics of getting the vhdx files into the appropriate array virtual drive since my practice run has stored my empty virtual drive vhdx files on the C drive with public documents? Could you enlighten me?

Would you recommend a separate virtual drive based on the small array for just the OS as I do with my older server? Two of my databases save backups to their same volume, and I have to go in and remove old unnecessary backup files to free space. I don't want the OS affected by space limitations and affecting everyone on the network. Yet the New Virtual Drive Wizard isn't helping me split the small array into two virtual drives, and it won't let me make a virtual drive of my large slow array by any other means than the dynamically sized type. Not what I want since that array is twice the size of the older large array. Any recommendations for these virtual hard drive problems with my specific application? A different method of creating virtual hard drives?

Thanks,
Dan