Technically, yes. As apple cider ages, it turns into apple cider vinegar. But you shouldn't substitute them for each other!

apple cider vinegar tablets are different to apple cider vinegar because they are tablets

Apple Cider. That's all it takes is apple cider fermenting with the help of some yeast into vinegar.

Apple cider vinegar is primarily made from apple cider, the alcohol in the cider having been oxidized to produce the vinegar. Apple cider is in turn made from the fermented juice of pressed apples.

Yes, the mixing is possible.