There are many rookies and former rookies who thought all they needed was some clever ideas, a circle saw, some MDF, and a Parts Express catalog and they could build some great sounding speakers. This is a guaranteed way to waste your money and time. So far, the ideas in your original post qualify you for a
Rookie DIY Speaker Builder Without a Plan t-shirt. No insult or offense intended, but you really should stop right there.
The methods for designing sealed or bass reflex cabinets for bass performance are clearly worked out and are very well explained in books such as
Speaker Building 201 by Ray Alden. I strongly recommend you buy or borrow this book, or the one by
Vance Dickason, and spend some time reading and understanding them. This is the easy part.
Once you understand cabinet design, then you can tackle the more complex problems of 2-way design and developing a crossover. Then you might be ready for 3-ways.
If all this sounds interesting, go ahead, get the books, and start reading. You should also get ready to spend some money on testing gear and design software, and spend more time learning how to properly use them. There are no quick and easy shortcuts to designing your own good sounding speakers.
If you really want to build some good speakers just once, I strongly suggest you build a kit or proven DIY design. There are many published on the internet that were designed by people who know what they are doing, and have been extensively tested and trouble-shot. Ask, and I'm sure people will have some good suggestions.