Because your code is so long and there has been cut-and-paste issues, as a check
Variables[Integrand]
results in
Are these the variables that you expect?
Thank you a lot for letting me notice the mistakes in copying my code in the question, now at least the Integrand should be ok!
Crossposted here. As pointed out in the crosspost Integrand does not evaluate, it has unbalanced parenthesis.
Integrand
