Help with posing & lighting

Did an informal school photo shoot for my niece ā light started too bright then quickly became too dark! Iām very inexperienced with posing, and lighting ā first time ever using a bounce illuminator and only have a SB400. Looking for honest feedback on posing and lighting mostly ā but whatever else you see too. Thanks in advance; I really appreciate it!
Fingernails got blown on #2 (they were hot pink) - what could I do about this during the shoot? What about to fix in PP?
Smugmug gallery with remainder of photos available here- http://bit.ly/hGbny
Scott Vander Dussen
#1

#2

#3

#4

Fingernails got blown on #2 (they were hot pink) - what could I do about this during the shoot? What about to fix in PP?
Smugmug gallery with remainder of photos available here- http://bit.ly/hGbny
Scott Vander Dussen
#1

#2

#3

#4
