For what it's worth....these things are very much forum dependent. Bogs are considered filters in this forum while in other forums they are not well thought of. Settlement chambers haven't been popular in higher end ponds for a long time. The question is how well something works. At the higher end people do a lot of testing to see if things work. In water gardens very little testing is done, very little data use to justify stuff. "I put XYZ into my pond and my pond is great, so everyone should use XYZ". Opinion and fact are often confused.
A bog is a settlement chamber...great at accumulating muck. Unfortunately they're impossible to clean (flush). I like a bog in a water garden for plants but I don't consider it a filter. Really the opposite of a filter as lots of stuff grows in the gravel and creates waste, more than is removed. Dig down into any bog that's been used for a year or two and you'll understand pretty fast.
Long ago (20-25 years) bogs were called "gravel filters" and "up flow filters". They fell out of favor pretty fast as testing showed they didn't work very well.
Vortex and other types of settlement chambers, and various pads (Skippy) were very popular 20, 30 years ago, many designs. Testing showed very effective.
Proper mechanical filtering is a multiple stage deal. Each stage removes smaller and smaller bit. Cleaning these is a big part of their design. It can get extreme. Doesn't sound like you want extreme. So why go there? Water gardens are fine without any mechanical filter. In Koi ponds mechanical is used so more fish can be added and owners often want the clearest possible water to view fish. In water gardens just plain clear is good enough for most people. Depends on what you want and length you're willing to go to get it.
Bottom drains...oh boy. In the water garden world bottom drains focus on the drain and it being on the bottom. In higher end ponds people see this as a system. Their are Tangential Pond Returns (TPRs) positioned around the pond to push debris to the drain, otherwise the drain only clears a small area around the drain. Same deal if you vacuum your living room by leaving the head in the middle of the room, very clean near the head, not so much everywhere else. You can sweep stuff to the head however.
Once sucked up where does the waste go? That's maybe the biggest rub. If waste collects in a settlement chamber (bog) it rots. What difference does it matter if it rots in a bog or in the bottom of the pond? Water quality suffers the same (although a bog grows more waste than non-bog). In a high end pond where max fish load is desired water quality is a big issue. In water gardens it's virtually never an issue. Perfectly fine to have some muck in the bottom of a pond or in a bog.
The current standard is to pair a bottom drain with a sieve filter. That removes waste from the water 24/7. After the sieve can be other types of filters if desired.
The question is what kind of pond do you want? Do you really need a bottom drain system? It doesn't sound to me like you really do. Why make it more complex than needed? IMO vacuuming works great. Leaf vacuum maybe once a month in summer and silt vac maybe once a year. Although if you leaf vac often enough (1 or 2 times a month) you may never need to silt vac. The pond itself acts as a settlement chamber. For more info here's my vacuuming page:
http://www.waterbugdesign.com/pond/vac.html
I like skimmers. I make my own:
http://www.waterbugdesign.com/pond/skimmer.html
I also like a catch basin the waterfall goes into to keep the pond surface still for better fish viewing and you never have foam on the water surface.
Be really careful about info sources. Opinion that sounds like fact, experience? Or backed up with verifiable test data? It's the internet.
