Can I insist upon a preventative cerclage after having suffered a loss at 23 weeks due to amniotic infection that caused the sac to protrude?!

Don't insist! There is still a lot to learn about the continuum of preterm birth, but cerclage should be reserved for two or more consecutive midtrimester deliveries, or a shortened cervix by ultrasound (<1.5 cm) between 16-24 weeks. Other therapies include 17-hydroxyprogesterone caproate injections, vaginal progesterone, and early pregnancy treatment of vaginal infection/inflammation. Confer with your ob!
Agree with "don't" The problem with insisting is, sometimes, that some doctors might give you what you insist upon even if it's not appropriate. We don't like to think about things like, that but it happens. It's always better to express your concerns, ask questions, then arrive at a course that both you and your doctor agree upon. Remember, you can always get another opinion if you disagree.
Depends. Cerclage is a procedure that helps the incompetent cervix to sustain the stress (pressure) caused by the gravid uterus. If your cervix measurements are normal (length, consistency) and no prior hx of cervical incompetence, there may be no need for cerclage. This is to be decided by your OB provider. Amniotic infection might have resulted from premature membrane rupture and this is a separate issue.
You can try. But you can never force a doctor to do something that for good medical reasons that should be explainable to you, they do not feel is not best for you. They should always explain to you the reasoning and together you should come up for a plan that is a good solid medical plan.