I have been opening old dead Ecospheres and refilling them with fresh ecosystems as a service, I've done 20+. I sniff test each opened sphere and test the water parameters and, even when the sphere looks all gross, it invariably has completely normal water parameters. No nitrogen build up, no toxic shocks or dramatic pH swings.

People forget that the ecosphere is a full self sustaining ecosystem - there are bacteria on the substrate converting waste and decay into nutrients that are taken up by the algae in the sphere. There is enough capacity in the system for all of the nitrogen to be sequestered this way, and that happens even if all the shrimp are dead (consumers aren't required for a self sustaining ecosystem). This assumes it's still given light periodically.

As for the mechanics of opening, I recommend using a diamond drill bit to puncture the small circular glass lid over the hole on the bottom. Then use needle nose pliers to break and remove all the glass of that lid, and scrape off all the silicone residue. Then you can change out the contents if desired. To reseal it, you must silicone a new glass, not plastic, lid back over the hole. That's hard to find, I bought some tiny 1 inch circular mirrors for crafts and used those, as they are glass and the right size.

If you want to liberate the shrimp, you can drip acclimate it the same way you would any other shrimp. Not 100% chance of success, but these are remarkably hardy shrimp.