Yii, Laravel, CI & Cakephp are best known php frameworks in market, I would like to know / confirm that does all these above frameworks works efficiently with NoSQL databases like Cassandra or Mongodb?
I'm sure that you can work with Mongo from all framework that you need. Example from google:
Select Framework that you like or have experience. Each of them have great community and solution work with NoSQL DB.
Regarding server side validation. Why not? Server validation should not connected to selected DB.
Difference from MySQL that if you enter invalid data it show you error. In NoSQL that value accepted. But correct behavior work with DB it's validate information before it pass DB. So first you validate POST then if it valid pass it to DB.