I don't consider sexy shrimp of porcelain crab clean up crew at all. The porcelain is a filter feeder so unless it is a small particle in the water column it isn't going to be eating it. Not sure if you have seen how small that sexy shrimp are either but do know that there is a good chance you'll not see them very much in a 90g. Same is true for a porcelain.
I'd also avoid the blue linkia I risked one and it injured itself and never recovered and I regret ever putting such a beautiful creature in a tank that I may not have even had the right food source for. There are many sources that will tell you that they have no idea what the eat. Pretty darn difficult to make sure you can keep it healthy with that considered.
Some of the worms could be tube worms and could be alive.
For diatoms in a 90g I'd suggest ceriths and turbos. I'd get some nassiarus after a bit longer but not to eat what you see on top, but rather to eat what you don't see in the sand. I have a florida fighting conch as well, they are great for the sandbed and with a 90g you may really enjoy one as well.
I do agree with what others have said about not trying to stock all your clean up crew at once as well.