[Ibvee]

I doubt it is a good idea to spend 10K when you don't even know how to hook it up.
Unless you're sure that you'll earn the money back, I wouldn't do it if I were you.

But to help you out.
What do you mean with presonus based studio? What piece of presonus do you mean?

You can control the volume of your monitors from your computer with the software, be it the software of your audio interface, or with your DAW. However this is not an ideal situation, because you wouldn't be using your full 24-bit in the converters. This is where something like the central station comes in. It has an analog (and even passive, which is supposed to not change anything except for the volume) volume control, which doesn't make you lose any bits when converting.

Hooking up outboard to a presonus interface, entirely depends on which specific interface, and which connections it has. However, I would advice that you don't buy any of that yet, but first get some more knowledge and experience. Buy a microphone, and use (if available) the preamps on your interface. If you need processing, use plugins, and find out what you like. As you go and learn, you'll find out which sort of outboard gear you need first and most. Try reading here, and elsewhere on the internet, about the theory of recording, and how things work, and should be connected.

A batchbay can be very handy for making connections when a lot of outboard gear is involved, but this will be very complicated if you don't even now how to connect things without a patchbay.

Yes, it is possible to mix in the box, and use an outboard tube compressor with mastering. But unless you really now what you're doing, and you've got some badass tube compressor (think $2000 and up) you'd better leave it to a proffesional mastering engineer, and worry about making good recordings and mixes yourself.

Furthermore, drums are all but an easy thing to record. Try to find somebody with experience in your neighbourhood, and learn from him, before spending a lot of money.

Protools doesn't support VST plugins.
Unless you have a personal preference for Protools, or you have to exchange sessions with people using Protools, there's no reason to get Protools. However, if you're into electronic music, I would do the contrary, go with Logic (on mac) or cubase.

I'd really advice not to buy anything except for a good interface with software, monitors and 1 or 2 proper microphones. When you buy everything at once right away, you have no idea what you're actually buying. So once you've actually learned how to use it, and what it sounds like etc. you'll regret buying half of it, and sell it, and lose quite some money in the end.

I hope this helps