The Sith have the ability to make lightsabers more powerful than the Jedi due to synthetic crystals; do they have the ability to up the midichlorian count in a person synthetically as well? Can they give Force sensitivity to someone who doesn't have it? And can they amp up the Force powers of someone who already is sensitive?
This is false. There's no such thing as a more powerful lightsaber. That's nothing but trash from one of the trash stories from the EU. Has never had any basis in canon, before or after Disney. The reason the Sith use synthetic crystals is:
1. The Jedi know where all the crystal caves are and it is a Jedi ritual for a padawan to get their first crystal. Therefore most of the caves are watched. The Sith have been in hiding for 1000 years, do you think they would risk it for a stupid crystal?
2. The Sith dont care about crystal rituals, or lightsabers in general.
3. The color of the Sith order is Red, and crystals dont come in that color.