The static ports don't NEED to be in the switch band, that's just where it makes sense to put them if you happen to have one. You need a place that cannot be blocked by the parts shifting in relation to each other etc. and the simplest way is the switch band. Same reason you put the switch there. There are loads of other ways to do it, but for a first go at dual deploy, the classic design is simpler and less likely to cause issues for you.
Shear pins are not really required, though they do help a lot to prevent main at apogee. You could, for example, make it a tighter friction fit with masking tape. But the pins are more reliable. Whatever you do, ground test over and over to ensure you know what happens with a couple charge sizes. You want to KNOW that the pins will shear and the nose will separate with (for example) 1g of powder the way you pack it in your charge holders. You also don't want so much that the recovery system has to absorb huge shock loads from the charge. I like to ground test till I get the same results with the same charge at least 3 times. For most rockets, #2 nylon screws are a good choice. For the apogee event, you might not need pins. Many people just make a snug friction fit. All you need to prevent is drag separation, so a small vent hole in the body tube and a snug fit is generally good enough. If you want to be really sure, you can pin it. Either way, ground test.
Drogue size isn't that important and there is room for a lot of debate on the ideal size. My opinion is that having a small drogue is good, but it doesn't need to be much. You want the parts falling at a pretty good clip. I've done drogueless with just the harness holding the parts together as well. It works, but it seems more prone to tangling the main so I don't do it anymore. I want the parts to fall in an inverted "V" shape, too much drogue makes them parallel to each other, increasing the risk of tangling the main.
As mentioned, the apogee, NOT the main, is the important event. If your rocket and motor allow for it, use the motor eject as a backup apogee event. Just use a delay a couple seconds longer than you would use normally. Perhaps increase the powder in it. The idea being that if the apogee event fires but doesn't separate, use more power for the backup.
Make sure the powder can't move in relation to the ematch. If it's anywhere close, it will "probably" work, but that's not good enough in my opinion. I want to know it will work. I pack it with dog barf and tape over the end to make sure things aren't moving around in flight. Another option is to not pour loose powder in at all, put it in some sort of container and seal the match in there.
Take a breath and relax. Overthinking and over-worrying will make it worse and make mistakes more likely. Make a checklist, and follow it. Make certain that you don't put things in backwards, main at apogee is more likely that way.
I can't stress this enough... REMEMBER TO ARM YOUR ELECTRONICS.
