Hi – if you have your heart set on not having a return line that goes up and over the lip of the tank, I would direct you to Herbie for Dual Overflows. Option 3 would be closest to what you are describing. Using all 4 pipes as drains is a better way to do it though.
It sounds like you understand the pipe diameter part of it, always use the larger of the two bulkheads (1″ in your case) as the emergency drain and the smaller one as the siphon valve drain. Also yes – there is not much benefit to using larger pipe size for a run of pipe if it ultimately must squeeze through a narrow opening like a bulkhead. The narrowest part of it determines the flow rate.
For the return, the only experience I have with spray bars is when I had a canister filter. If your goal is to move fish waste around I would skip the spray bar and use an outlet to boost flow in the tank.
As for water levels in your particular tank concerning the weir teeth, I’d say there are just too many factors and it would be hard to give you advice without seeing the setup. So for this type of thing just experimenting yourself would be the best, such as setting the tank up in a garage or outdoors to test the setup and see how adjusting the weir height affects things.
Lastly – concerning the distance between the E-drain inlet and the top of the tank, I think when I wrote that it was just to get people to think about that generally.
If someone had a super strong pump and no room above the E-drain inlet, it could be possible to have water spill over the top of the tank. Unlikely but not impossible, just something to be aware of.

If you are doing a siphon inside an overflow, it needs another drain in the same overflow. No getting around that. In other words you can’t have a siphon on its own.
What you described sounds like Option 3, so you would just have to consider the weir heights of each overflow. I do think you could get adequate flow in a 220 gal with only 1″ pipe.

I will probably update the section where I initially recommended under-over-under as a baffle configuration. In practice I prefer over-under-over just because it reduces the area where surface scum can accumulate. On my 40 gallon sump I ended up adding another baffle to the skimmer section which makes it over-under-over (3 baffles) instead of just under-over with 2 baffles.
As far as your question about Chaeto, I run a decent amount of it in my return pump section separated only by a piece of egg crate that doesn’t even span the whole width of the sump. It keeps the main clump of Chaeto separated but smaller pieces float around a bit. I also use a fish net to remove most of the smaller bits of Chaeto from the sump every other month or so. My pump is a Jebao DCP-6000 and has a built-in strainer on the intake. Even with doing that, sometimes the odd couple of pieces of Cheato get into the pump and into the display. So far no issues. I find strainers easier to clean than sponges.

It’s made of 1/2″ HDPE plastic sheet. The key is to get the hole size correct (I used a circle cutting jig for my trim router). You want the sock to wedge in slightly so it doesn’t float up.