Hello, i will answer this questions with the best of my abilities.
1- This sprites have commercial and non commercial use, for almost any purpose except you can modify as you see fit, except share it or resell it.
2- You will have a modified(better) version of all the icon packs i described on the list in the end of the page, further it is all the sprites i have currently except for one (dark fantasy) intended to be a standalone product.
3- Yes, you will get everything i released until today for 5$ and will always get everything while you stay as a patreon, the new products i mean.
Hope this helps, Regards ;)