If the main question is about getting them here, the main issue, even in cargo is the number of pets permitted on a flight.
It looks like you have everything else covered in the comments.
I brought 6 pets with me. The paperwork and everything else was a PITA to do, and also used a pet agent both sides. As money isn’t an issue, I would say this is a must.
You can also find pages for Flight volunteers (I do this) where you find someone flying the route to be your pet companion. Most do this for free… I suspect you will struggle to get all on one flight, but this would save you going back and forth. Feel free to PM.
I have 5 cats that I brought to Thailand and they are fine. I keep an eye out for snakes but as they have always been indoor/ outdoor, I decided that their comfort whilst they are with me is more important than the chance they may get killed by a snake. That being said I’ve had them in SEA for 7 years, and no problem so far.