That's not even remotely detailed.
This might help but 3d printing will also teach you a lot.
https://www.3dhubs.com/knowledge-base/how-design-parts-cnc-machining/Couple things to add.
Designing in digital is quite different than hand creating, but also blueprints, you may think well obviously but you don't really grasp how different until the part comes out and you hold it in your hand. You can get "lost" in digital editing and not realize where you are, how large something is. You can also forget and but heads of screws against other heads of screws (meaning no way to put them in) as well as simply forget to allow tool clearances or worse, and I speak from experience here, completely miss a hole. It's easy to spot something out of place or something extra but seeing something missing is quite a bit more challenging. This is why 3d printing is so valuable, you can hold the part in your hand or even test fit before sending it out for machining allowing you to notice you forgot a hole or that something is off by 0.25mm. If each attempt costs $500 (the low end for a one off) it's pretty easy to see how spending $200 on a printer will pay off.
Most cnc shops are geared at production, the workers like one-offs for a change of pace but it hurts the bottom line. As such you will have the lowest priority and easy to locate shops are usually backed up for months. You start at the end of the line and get pushed back over and over until they either cram you in, have downtime or you give up and go elsewhere. Check places like Craigslist, you may find a guy with a smaller, cheaper mill in their garage willing to take smaller jobs like yours for a fraction (they can also point you towards good larger shops if need be). These guys are also often willing to help make changes to make it easier to make. Anodizing shops are similar, they are used to industrial applications, not decorative, so you may need to temper your expectations or be prepared to shop a round for one who will take their time and it will be a hassle.
If you can laser/water jet it rather than CNC, do so, this is why many cases are plate cases, it is a LOT cheaper and faster. You can get it back in a few days if you laser or water jet as opposed to weeks/months on cnc and at a mere fraction of the cost.
If you're in the US and design in metric some shops will refuse the job or force you to covert it to "standard" before they will take it. I don't get it, but we had it happen at my company.
Getting printer has plus and minuses, you can test and test and test for pennies once you have the printer but you can also get stuck in an endless cycle of revisions, "just one more change and I think it's done" only to get an inspiration later and think "I should have done it this way instead" and start the whole thing over again. You also need to learn the printer and it too has specific design challenges. Think of a house and you need a doorway, on cnc you start with a wall and just cut out the door, on a 3d printer it's more like brick laying, you start at the bottom and work your way up and then you have to find a way to bridge across the doorway. You can end up with the same product, you just have to come at them a bit different (also depends on the type of 3d printing to be used).
China makes it easy, but not really. Communication issues can be a problem, shipping can be a problem but while they can make quality if you pay for it the real problem is just misunderstanding. You can't just drive down and show them what you want or need. They also have different standards for things, not just quality, what happens a lot with pcbs is you send them all the files and they either don't look, lost them or simply don't understand the format, I'm not sure but many times I've seen people have issues where they claimed not everything was sent. Regardless, China is like dealing with the mob, don't like it, too bad, pay me. Not up to standards, too bad, pay me. Wrong size, you should have specified, pay me. No matter what, if you do business there, DO NOT under any circumstance pay with Western union. You really have little recourse in any case but Western Union is even worse and they know it. If they push for that payment method, run, don't walk. They tend to setup multiple fronts for their business because it's cheap and many of them will just close down the front and start another while walking away with the money. I'm not saying they are all scams, we worked with some fantastic companies over there and while there are scammers here too, at least at home you understand the legal system and have more options for recourse. Larger companies often send a representative to live there during production to oversee it and make sure it's done to their standards otherwise you have no idea what you got until you open the box. I really wouldn't send something over there until you have a grasp on what you need first.
Good luck, the easiest, cheapest part of the entire process is the design, it only gets more difficult from here.
If you do go through with it (and I won't blame you for not) show us the results, costs, issues, etc...
