Russia doesn't really differentiate between right and left when it comes to trying to destabilize Europe, they throw random shit against the wall and then focus on what sticks.
You may be confusing the Soviet Union (disbanded in 1991) with Russia. The Soviet Union (USSR) was communist, but Russia existed before and after the Soviet Union. Russia was a monarchy before 1917 and became a semi-presidential republic (under Putin) after the fall of the Soviet Union. I would also describe modern Russia as an oligarchy and certainly seems to be far-right in terms of politics.
Yes. Trump is a New Yorker. What do you think his party was when growing up? By the way, he has swapped political parties like he probably showers: every few years. Trump has been a democrat, registered, donor, everything you want, multiple times.
Only in one sense. You get Russian money if you're extreme. Left, right, muslim extremist, anarchist, ... doesn't matter. As long as you're willing to sabotage Germany. But the CDU (and even Die Linke for that matter, everyone vaguely "normal") has to get it's Russian bribes the old fashioned way: with large industrial projects. No freebies.