I am building myself a lanyard for my waterfowl calls. This is just for me, I'm not planning on labelling myself a "professional lanyard maker" and hanging the "lanyards for sale (professionally made)" sign.
I have the following requirements - It needs to hold 2 goose calls, 1 duck call, 1 pintail whistle and 1 Fox-40 whistle. It needs to hold the duck/goose calls securely at barrel and keg.

So, I started myself a prototype last weekend that includes a harness ring at the bottom for whistles (the neck loop is cow-hitched to this ring at both ends) and 4 small D-rings for attaching droppers. The braid is a 2 color snake knot over a 2 strand core. I like where it is headed and I'll post a picture tonight when I get home if it helps with my questions...

1. Is there a knot that is maybe better than a snake knot for a lanyard?
2. Are the D-rings a good/bad idea? I see lots of guys just clip the dropper to a strand in the location they want, but I can see that possibly causing rub damage to the cord its clipped
to(?)
3. Is there any need for adjustability in the neck loop? I just made it big enough to fit over a baseball cap and around my neck while wearing a hood (sweatshirt).
4. Am I missing anything? Any best practices I didn't think about?

When I made mine I used para cord. The loops were just a noose knot ( not sure the proper name)

Make the neck hole big. Make the drop loops long. When you're bundled up in zero degree weather you'll need the extra size and length

I'll answer #3.

I'm a fan of adjustability because I hunt a lot of different scenarios. There is a big difference between being doubled down in a blind, laid out flat in a field or crouching in standing timber. I always prefered my lanyard to be a little bit more loose than the generic ones that you can buy.

As for D-rings, I'm not a fan of anything that could rust or clank against any acrylic calls by accident when I'm moving around. I've had my go too lanyard for 25 years and haven't had any issues with the cord fraying from normal use where a d-ring would be needed.

Just my $0.02. Looking forward to see a pic.

I miscalculated the amount of paracord required so I had to add the large ring at the top. You can see only half is wrapped right now
I think I need to try again, but I do like the feel of it so far.