You've forgotten one plan-changing element: power. Sewing machines (especially computerized ones) and sergers and most especially irons really require dedicated power sources and power strips with a surge protector. Can your machines go where your light sources are? or are you going to have to get power to your machines in a less-than-optimum way?

Also, where it comes to light, you really can't have too many light sources. Better to not turn some on than to not have enough!

Another thing that's worth considering: buying those translucent or see-through plastic drawers is great and I highly recommend them, but does mean two things: your initial outlay will be fairly large, so start saving up so you can buy them all at once...because...whenever possible buy all the same height units. I like the stacking ones, myself, as you can stack them as tall or as short as you like, and dependent on whether you need storage on top of them running across several units, or wall space above them for display, etc.

I found the hard way that if you buy units at different times (on sale, for instance), they're almost never the same height. Buy the drawers in a deeper size rather than a shallow one -- better to have too much room in a drawer than not enough.

Also: take out the carpet. Threads in carpet = mess.

My, let's see, 10 cents. :)