I gotta hustle home...: Tutorial: Turning a womans shirt into 2 piece pajamas

Hello! I made a pair of PJs for Lily last week out of a womans shirt that my mom wouldn't wear, so I thought I'd try it again, and post a tutorial this time.
Right now I'm only posting the pants section, b/c I have to do a few things today before I can start on the shirt, but at least this might be able to get ya started :)

First you want a shirt that is kind of big. I'd say a lg or xl. that worked well for my 12-18m pjs. You also need 1/2" elastic, and a serger will make your life easier on this, but it's not totally necessary.

Here is the shirt I used. If you notice, It has small seed beads and bugle beads along the neckline. I started by clipping the strings the beads were on and removing them all. This is important b/c you will likely remove part of the top of the neckline in order to downsize the head opening. When you do this, you will cut through those strings, and after washing or wearing, the beads will come off which can pose as a choking hazard.

Reconstruction: Womans Shirt to Baby PJs

Now you will cut the sleeves off. Cut as close as you can to the original seam.

It really helps to have a cheering section

Now go through your child's closet, and find a ready to wear (RTW) shirt that fits the way you want this shirt to fit. And a pair of pants (preferably not jeans, you'll see why) that fit the way you want the pants to fit (not necessarily cut, but inseam, length, etc)

Here's the shirt I picked

Then flip it inside out, while leaving the sleeves inside.

You will use this for your shirt pattern here in a few minutes.

Over on the cutting board, we have our sleeves, and our pants

Flip your pants inside out, leaving one leg inside the other. This will expose the "J" shaped crotch seam.

Move one sleeve off to the side.
Line the hem of the pants up with the hem of the remaining sleeve. If you need to add some length (like I did) you can just slide the pants up as far as you need to add. Ie. I wanted to add 1 inch, so i slid them up one inch.
Now pin just slightly above the waistband on your sleeve.
Measure your inseam and full length (top of waist band to bottom of hem). Write these numbers down if your memory sucks as much as mine does.

Now remember, at the top you have to allow room to serge your raw edges, fold over and insert elastic (or turn, case and insert elastic, if you prefer) so we are going to add about 1.5" to the top of the pants. Pin that spot too.

Now I used my other rotary cutting board (smaller) and used that as a straight edge. I used my rotary tool to cut in a straight line at the top pins

Grab that 2nd sleeve you set aside, Put the cut sleeve on top. Line up the bottom hem/lace as perfectly as possible. If they are very uneven, you'll have uneven inseams.
Cut along line (I used my mat as a straight edge again)

Grab the RTW pants you have out, and lay them back down. Line up the bottom of the jeans with the bottom of the hem (or up an inch like I did). You should still have 1 pin just a hair above the waist line.
Now line up the outside seam with one edge of the sleeves.
See that J shaped curve in the crotch I talked about before?
We're going to pin along that shape, leaving a very small seam allowance.

Cut it out

Clip the sleeves right side out, and you'll have this

Flip one sleeve inside out. Place right-side-out sleeve inside the inside-out-sleeve. This will make your right sides face one another, and allow you to serge the crotch seam without too much fabric to maneuver.

Serge around the crotch seam (it will go from center from waist to center back waist) being sure to line up the raw edges. Don't worry if the top of the pants (waistband) area isn't completely straight. If it's not, it's probably b/c when you cut it, it wasn't a perfectly straight line, and that's okay. You'll serge off some of that anyways.