Unexpected defeat of the leader and other questions/issues

Hi Guys,

I just played my first longer game (singleplayer) which more or less ended abruptly to an unexpected defeat of the leader. I was playing in an immense galaxy with about 11 other parties on normal where I was in place 3 and at war with 2. I was first in Tech and Treasury , 2nd in Economy and 3rd in everything else (well at least on the diplomacy screen , I think unknown races are not included?).

The war itself was pretty uneventful and have my doubts that the fleet strength is calculated correctly. I had more than 40 bigger ships like Overlord, Destroyer and Ranger and he never attacked with more than 7. But from the graphs I was not even near his strength. The fleet AI in itself was very clunky. Why can you not assign fleets like in any other game? You have to go through the ship list or search for them on the map and drag them on the same tile. Very inconveniant. Apparently it is also not possible to attack from more than one side? 

Now while I was slowly invading his planets on after another (which is way too easy and annoying from the other side , just fill a transporter and go ) I get the message that Pos.1 had been defeated by Pos.2. Seems like they were at war too. The funny thing is I got all his "remaining" structures (why? I had an NAP with him but that's it nothing more) Anyways, this just increased my colony nr from 20 over 100 hundred. The dude had like half the galaxy. If I adjusted the gov slider to the middle I suddenly had 15k research points whereas before I had about 2000 and was leading by a landslide in the graphs. How can that be? What happened here? Why did he lose? And how was is possible for him in the first place to gain about 3500 Fraction Points in the last 150 turns when me and the other dude gained maybe a few hundred? Did he cheat or something?

Thanks for the help!