I have rehydrated my yeast both ways and the "just sprinkle it in" can work. That's how I did it before, now I do so with warm water because I read that more of the yeast survive that way. You can damage the yeast if you add it dry directly to the wort, but many will survive and you will still get OK fermentation.
I have tried the Beano trick once, and for me it was not worth it. I wanted to get that extra drop in gravity points and I think what I got was only an extra .001 OR .002 . But others may have had better results. Not worth the risk of picking something up in my opinion. I added the beano to the seconday. From what I read the simple version is that Beano contains an Enzyme that transforms the non-fermentable sugars to Fermentable sugars.