Westlake Academy and their IB program has been a highly recognized and a strong draw for the school; however, they have had some leadership changes which has concerned some parents. I would recommend touring the school and deciding for yourself and your family. As for Keller vs. Carroll ISD, yes Carroll is Exemplary at the upper levels, while Keller is recognized. There is some variance at the individual school levels.
As for Vaquero vs. Terra Bella, it will also depend on individual preferences. Vaquero is an established community while Terra Bella is in the beginning stages. In the near future, some individuals will prefer an established neighborhood. Vaquero also offers access to the clubhouse and golf course which will help in resale. Vaquero also has a strong name brand due to who lives there, which also makes it have an edge from an investment perspective.
So from an investment standpoint I would favor Vaquero, but you will still need to determine if the property that is available will suit your needs and if it feels like home to you. From your statement above, it appears that it does suit your needs.
If I can help you further, you can reach me at 817-726-9663. There are a lot of hurdles in buying the property and building a home and it is recommended that you have an agent assist you.
Century 21 Judge Fite - Southlake