When reciting the alphabet in French, the "w" is pronounced doo-bluh-vay. This literally means "double v" and is similar to the Spanish "w." (Spanish is another Romance language where the letter "w" is not native.) In use, the letter "w" is found primarily in words borrowed from other languages.
Future Trunks has been stronger than Vegeta in several points in the series. The beginning the Android arc, Vegeta was terrified of Frieza and King Cold but Future Trunks beat them both easily. When he fought Perfect Cell he had more raw power then Vegeta.
In other words, Umbridge didn't need to become a Death Eater because she was in a very real sense a Voldemort Ally. She was way above any Death Eater when it came to political power, and she was eager to work with Voldemort in a political alliance as the Ministry's highest official.