That actor was Sebastian Shaw
Darth Vader actually is Luke's father.
Actually, Darth Vader is Luke Skywalker's father
Yes, Luke is. Watch Episode 6 when Luka and Vader are walking up the steps in the Death Star. Luke's head comes to Vader's shoulder, and Vader was about 7 or 8 ft. tall.
Yes
Luke meets Darth Vader in the Bespin system, at Cloud City which is above Bespin.
Darth Vader was Galen Marek's master, and Luke Skywlker beat Vader. So I suspect Luke would outclass Starkiller.
No. At the end of Return of the Jedi, Darth Vader saves Luke and dies.
Both the movies and the novelization revealed that yes, Darth Vader was Luke's father. Darth Vader claimed to be Luke's father in "The Empire Strikes Back", Obi-Wan and Yoda confirmed it in "Return of the Jedi".
No. Darth Vader was formerly Anakin Skywalker who was married to Padme. When Anakin fell to the Sith, Padme had the kids who were hidden from Vader by the Jedi. That's why Luke was hidden from Vader
He was his son
Not at first. Not until Vader told him himself and was then confirmed by Yoda.
He didn't Palpatine did when he got picked up and thrown down a pit by Vader (Vader got electrocuted).