Tbh, I think it's a way too high budget for a starting botting RIG.
Usually you can start with a budget RIG for like 500-800$ and upgrade when you start to make profit, a budget computer can run 5 bots easily. Can probably go to 7 or so. The only thing you should consider is Scheduling it correctly, and automating things.
For example, my budget RIG close/starts himself, from X to Y hours and on start, I have a couple of batch files that starts everything out automatically. Like this the RIG don't have 24/7 uptime and components last a bit longer.
Used it a while ago for D3 botting (RMAH BRAH) and I've made shit ton of cash with it. to cash out, there's no point having 20 bots, 5-10 is enough until you get your money back from investment. after that, keep running, when they get hit by those famous "administrators" refresh things up, and consider upgrading, and so on...
But well, always have an SSD for OS, not sure about the VMs tho. If you can get a decent 240GB ssd it can handle like 10VMs or so.