You can call the Clerk of the Court of the county where the case was tried. 

He will definitely get credit for the six months he did in county. He probably has to do 85% of the sentence (assuming he stays out of trouble and remains incident-report free). That would be 25.5 months. What jurisdiction did he get sentenced in? Where did you see the release date (that might not have figured in the good time as of that listing)? 

This sounds like a state inmate that has been transferred to a contract prison in another state due to several possible reasons. One is overcrowding, the other could be if he has a codefendant in the same prison (they separate them), third could be disciplinary, it could also be that they have a court date and need to be within a reasonable distance from the courthouse.

No, in-person visits only. Please go to https://www.inmateaid.com/visitation/rankin-county-ms-jail for the exact times and days.

We don't know the facts, but it sounds like he did something to jeopardize his release date. You can call the facility and ask to speak to the counselor, if you are a close relative they might confide in you.

No. The inmates are entitled to privacy in prison too. If you think he is calling someone, you know him better than anyone, he probably is.

Inmates are not permitted access to the internet. However, there are some services where an inmate can pay someone on the outside to do their posts for them. BUT, if he is harassing you, you can call the facility and ask to speak with the warden's secretary. Give them the details and request a call back or you are going to the local police. This could become a serious issue so be careful

Missing the court date is not a good thing but if he was already in jail on another warrant, it shouldn't affect him for missing. BUT, there is always more to the story and if his court dates about domestic violence what was the warrant for?  Because of the limited information, we have no idea how long he'll have to sit.

We would advise that you call the facility first to make sure that you and the kids are on the list and YOU don't get surprised.

It is entirely possible they could have problems. The inmates do not look favorable on men who molest, abuse or are otherwise convicted of a crime involving children or women. Depending on the terms of the crime, the inmates will decide if there is any retribution meted out.