What order to add fish to avoid aggression

[A sea K]

Sorry to interject, but do you have to buy the goby together with the shrimp, or will they pair naturally if placed in the same habitat together?

IME they will typically find one another and do not require purchasing a so called "pair".

Are tail spots considered a hardy fish I could add first?

Tailspots are fairly hardy in regards to taking man made prepared foods unlike some of their close relatives. I do not know how well they can tolerate unstable parameters but I have had them in some newly cycled aquariums without issues.