Your estimated cost of the villa is pretty close. For school fees, look at Doha English Speaking School website for current term fees. Qatar has zero income tax. So whether you would be better or worse off financially would depend on what the whole thing is worth to you. In considering whether it is worth it to come over to Qatar, do consider the effect on your family life, any family concerns re travel and distance from parents, relatives, friends etc, how long you want to be in Qatar and where you want to be or what you want to do after Qatar.
Your estimated cost of the villa is pretty close. For school fees, look at Doha English Speaking School website for current term fees. Qatar has zero income tax. So whether you would be better or worse off financially would depend on what the whole thing is worth to you. In considering whether it is worth it to come over to Qatar, do consider the effect on your family life, any family concerns re travel and distance from parents, relatives, friends etc, how long you want to be in Qatar and where you want to be or what you want to do after Qatar.