I am running a 10 year old esxi 4.0.0 host that I want to replace with a new system.

I have a Synology NAS on my network and have all of my vm's running within a single iscsi datastore on the Synology host, so replacing the esxi host has ZERO to do with any storage within that server, all of my vm's are on the Synology NAS.  The only thing the host is doing is running esxi itself, and connecting to the iscsi datastore.

So my questions are twofold.  Since I don't need any raid5 storage on a new host, can I buy a typical Dell XPS 8900 workstation with an i7 processor, lots of ram, and only a basic 1tb sata drive, just to install esxi itself, so the big issues of storage compatibility in the HCL wouldn't apply because all of my vm's are on the network and not local?

Then, if I can go buy a new, cheap system with minimal storage, do I have to upgrade my vm's in multiple steps from 4.0 to the latest version of esxi, or can I upgrade them in a single step?

1 current host, running esxi 4.0.  No local host datastore.

1 Synology NAS drive on the same network segment.

1 iSCSI datastore on the Synology NAS - allocated space 1tb, 50% available.

6 VM's within the 1 datastore.

No plan to upgrade existing host, too old.  Big old 3 fan server and not very green at all.

I want to purchase a new Dell XPS8900, Skylake i7-6700 processor, 8mg cache, 4.0 ghz, 32gb ddr4 memory, 2133mhz, 1tb sata standard drive.

Install latest esxi edition on new host with zero local datastore, just esxi host on new Dell box.

Need recommended procedure to upgrade datastore and vm's from 4.0 to latest.