Hi FTer's with children I really need your help.
I am Mrs. Nub2travel and I have volunteered to escort my nieces to Japan to stay with their father. Mr Nub2travel is not willing to go on this adventure with me so I doing this solo. We do not have any children therefore I am not used to traveling with children. What do I need to know? Please start from the beginning.

Some facts:
I have a passport
Parents are aware they will have to get passport for the girls.
Ages 4yr and 20 months
The girls and I do not have same last name
Parents do not have same last name (not married)
The girls do not have some last name (I do not know why) (confused?)
Brother lives in Japan & has just traveled to US May/June so can not make the trip himself
Mother lives in Kansas
Mother will be out of the country at time of trip. (military deployment)
Children are biracial and look more like mom (caucasian)



As stated above parents are not in the same time zone so I am very concerned about important details falling into abyss.
I not staying in Japan for a visit but I will want to give myself a little break before getting back on the plane. How long would suggest?
Can 20 month old travel in lap? I do not want this option just asking.

BTW
The more I think about this the more I am kicking myself for offering to do this.