Google "definition of probable cause." You're a student. You're supposed to know those things if you can find Avvo to ask the question in the first place. Or you could go to a law library and look it up in Black's Law Dictionary.
Clearly. The number of people convicted or exonerated because of stupid (or true) postings on social media pages is legion. Print off the pages and mail it to the DA. They are admissible as an admission.
An ALJ can't find you guilty of perjury or contempt. The case has to be referred to a prosecutor for a determination of what to do. We know nothing of the facts, but yes, you can get charged, and any time you're charged you can get convicted. Perjury is one of the worse crimes to be convicted of for moral turpitude offenses.