Crocheters! Help

1. Is 8 inches across big enough for a newborn sleep sack? And 17" down.
2. How many stitches around the magic circle/ how wide should the circle become before working downward for a 2 year olds hat. To clarify, how far should the circle measure across when it's folded on half and measured at the longest point before working on stich in each ( no more increases) for size 2t?
3.why is my color change always crooked, like the stripes are lopsided and not even
4. Which stich do you put stich marker in, the one on the hook or the one behind that because I use the stich or loop next to the one on the hook and the rows don't seem even, but I don't think that one counts as a stich??

I'm having issues lol

Are you using a pattern, or making your own?

<blockquote><b>Quoting Pirate Hooker {BAMW}:</b>" Are you using a pattern, or making your own?"</blockquote>




The pattern I like for a hat only has up to size 9 months so I'm trying to make it bigger, a mickey for my son and I made a Minnie for my daughter due in march so they can match  

The sleep sack is my own pattern since its really easy, not really much if a pattern, just around and around then narrowing until a point, just wanna make sure the baby will fit before I work on it further  

I've not made a sleep sack in a long time, so I can't even remember the measurements.
But I think it would be ok