Ok...thanks...I think your first paragraph answers my question. If I've interpreted this correctly, if we run a test and detect what slit a particle went through it won't effect a future test of the same particle? As for your second paragraph mentioning entanglement mind blown. I'm not ready...
WARNING. I'm not a physicist! If there was a universe that only had 10000 photons and we observed all of them then ran the double slit experiment would we get a normal pattern or an interference pattern? If we observe a particle is that it forever in the universe that we happen to be running...