Hoping to get some c&c on a few amateur attempts at backlighting..

[MommyOf4]

Hi, everyone I mostly lurk here and want you to know I have learned SO much here in the past year. I hope you dont mind me posting a few pics (4) I just read a thread on how annoying all the C&C requests were getting lol I do really appreciate your input if you have a moment. First 2 are just a couple of black and whites because I feel like my B&W images are lacking. Second are 2 attempts at backlighting. Just trying to figure out what works and what doesnt. I didn't use spot metering shooting them though, Do you always use spot metering for the subjects skin when using backlight?
1.

IMG_3746 by MariaBerio, on Flickr
2.

IMG_3613 by MariaBerio, on Flickr

Backlighting attempts
3.

Picture 5492 by MariaBerio, on Flickr

and with this one I almost HAD to convert it to B&W because he was so underexposed SOOC I think I have to mess around with spot metering?
4.

IMG_3566 by MariaBerio, on Flickr

 

[KmH]

All but #2 work for me.

I always used strobed light from the front, more so than post processing.

I used back lighting more for a rim, or Rembrandt type effect.