I was curious about M1. The how to videos show lifting the bar back to front and knitting thru the front loop. A pattern I have (FT Clogs) says pick up the bar from front to back and knit the back loop. If the pattern doesn’t specify can you do it either way?
I guess it depends on what you need it to look like. When I put the loop onto the needle, I knit into the back of it which will twist the stitch and prevent a hole (this is how I usually do M1). If you are doing lace type of work, you could knit into the front of it and I think that will make a hole in the work. If your pattern comes with a glossary of stitches, then follow what their definition of M1 is.
v.
When a pattern says M1, I always lift from front to back and knit into the back.
What Ingrid said. Plus, these are felted, so no one will really be able to tell in the end. 
If the two increases are on either side of a column of stitches, I Make one in one direction, and then one in the other direction. I use the make one where you make a firm backward loop over the righthand needle, so I make the first twist around my thumb, and the second twist around my left forefinger.