Epsom salt applied as a light foliar spray a couple times to fix what was definitely an Mg lockout is not dangerous at all.

Things look a lot better. I usually advise people not to try making funky soil mixes until they are comfortable growing in a basic boring one with nothing else added to it. Miracle Grow is not your best option for fertilizer though; you will end up HAVING to flush more often just to manage it, and it can definitely salt up the soil. Can you find pure blend pro or canna near you? Look at hydro shops.