Texas
What is a half cousin? It isn't a recognized term. Texas and Tennessee allow 1st cousin marriages. Pennsylvania does not allow first cousin marriages.
yes
Yes, unless it is a same-sex marriage.
Yes. Texas recognizes marriages filed in Nevada.
Texas would not recognize the marriage. Texas does not allow same-sex marriages, and the Defense of Marriage Act (federal law) says that states have the right to refuse to recognize same-sex marriages that occurred in other states.
As of June, 2014, The Texas law banning the recognition of same-sex unions has been overturned. However, it is stayed (on hold) until the appeal process can be completed. So right now, Texas does not recognize any same-sex marriages from California, but does recognize opposite-sex marriages.
US marriages must be dissolved in the state in which they occur.
In Texas, a person is allowed to be married to at most one other person at any given time. That said, there is no limit to the total number of marriages a person may have. Thus, a sixth marriage is perfectly legal in Texas.
No. The marriage certificate is not sufficient. You must also obtain a court order permitting you to change your name. This extra step is made necessary by Texas' refusal to recognize legal marriages between persons of the same gender, even though it recognizes all other types of marriages, even if the parties would not be permitted to marry under Texas law.
There is no explicit prohibition of adoption by a same-sex couple in Texas. Texas, however, does not recognize same-sex marriages. In some Texas jurisdictions, a person is permitted to adopt the natural child of his or her same-sex partner. Adoption of children by single gay persons is legal in Texas.
Success rate of love marriages is as good or as bad as arranged marriages.