Hi RW92
The WP for the fish tank are fine. Also the TDS for fish is not so critical as long as it is stable, providing it is not up super high like over 600 or so. I just monitor mine, as i use tap water and not RO, to have an idea where it is but never try to change it as i'm just to lazy.
The KH and GH are also good for almost all fish and would only need to be lowered for the shrimp to get it where you want. The remineralizer you have is for bringing up the GH and KH of RO water from 0 to your desired level. The lazy way, and much cheaper, is to mix tap water with RO and get the desired level. This does not work if there are other impurities in your tap water that you dont want and can be a bit tricky if your tap water changes throughout the year as some do.
The test kits for GH and KH are a general guide and give a pretty broad range, for drops in 5ml of water, of ppm. This can be converted to dKH by dividing by 28 (i think, can somebody correct me there). To get a more accurate measurement the water volume can be increased to 10ml. Generally if you quote the drops per 5ml water then most people know what you are talking about.
Adding bacteria to your water, in my opinion, is a waste of time and money. You would benefit from taking a sponge out of the established tank and putting it in the new tanks filter. Best spot would be at the start of the flow in the filter so any bacteria that gets washed out of it will be washed through the new filters media. That will cut the cycle time by weeks.
Keep the updates coming along with the photo's.