It shouldnt matter too much about CPU and RAM that much - the bottleneck with databases is always disk IO - so if you can get it to go faster it'll be worth it. 2 CPU and 4GB RAM should be fine - look at the utilisation on the server when you are using it - it should be fairly low - if not - add more
If its slow and laggy for one user - it will only get worse with more users.
Do you have any disk benchmarking software that you can use on the 'server' (either the VM or the host) to test the HDD speed? (would be worth testing both).
If its a laptop with a single HDD running Windows with VMWare Player or equivalent there is a lot of HDD overheads anyway.
You'd be better off having a dedicated disk for OS and a separate RAID array for the data - if its RAID'd you'll get data protection if a disk fails and a bit of a performance boost too.
A VPS with SSD RAID will be expensive but some VPS with a decent RAID 5 array should be ample for the blockchain - the SSD recommendation was for the laptop to squeeze as much performance as possible.
The alternative is to run the whole system from a RAMdisk and just use the RAM instead of SSD (lightning fast but will need a lot of RAM)
Can you provide some more details on your demo laptop specs?