Welcome. Will try my best here:
i) Define "groundfighting"? It generally does not teach grappling on the ground in the same style as Sombo or BJJ. It does however include a range of kneeling techniques, where both practioners start of facing each other from a kneeling position, and some of these techniques demonstrate restraints that can be applied on the ground. Certain styles of Aikido have a strong Judo influence, and have a range of supine techniques for tying an opponent up on the ground. Bu not all Aikido styles teach this.
ii) Yes, is a short answer. It contains so called "free play", where Uke (attacker) tries to overpower overpower Tori (defender). There are many variations on free play. Some invlove tanto (wooden dagger) and others involve, others empty hand techniques. It depends on the style of Aikido and the class.
These aren't great answers, but the questions you asked are pretty expansive. And generally, I don't like to generalize!
"Let your food be your medicine, and your medicine be your food"