the short answer would be no. inverts are really sensitive creatures. any small change in thier surroundings can have a negative effect on them. if you want to keep marine inverts like corals or prawns, the minimum SG is normally 1.022.
unless you can find any that are doing well in a brackish environment, i would leave them be.
i also think it may be illegal for you to collect native marine life where you live. i was speaking to a feller in california somewhere who wanted to set up a native marine tank, but it turns out you need a permit, and they dont give them out to just anyone... glad i live in the UK sometimes. i dont need anything to go collecting in rockpools for my native tanks...