Blueberry roots generally spread out as far as the top growth, and if you don't water them, they'll die. I'd recommend running a hose out to your plants.

I'd like to see a picture of your plants. If the "center branches" you're referring to are new shoots emerging, then you don't want to cut those out, as they are what will renew your bush. However, during dormant season pruning, it's recommended to remove the weak new shoots.

The specks are the seeds.

Do the seeds turn brown when the fruit begins to change color?
The brown specs I'm referring to only showed up on a few berries and appear rotten.

I have a hose that reaches the plants, but I use lake water because my well water is not ideal for blueberries.

The center foliage I want to remove are not shoots.
They are branches off the shoots that are growing towards the center of the bush causing a crowd in the middle.
I only want to prune the branches that are growing in, not the shoots.
Thanks for the feedback!

Yes, the seeds turn brown as the fruit ripens.

There's really no need to thin the shoots now. Make sure to not overthin them when you do, though.