This is going to sound dumb because I haven’t read any origins stuff (booo hissss) But was there a big bad evil empire-esque organization before the actual empire?

Well, I suppose it depends what you mean. The Bad People before the Empire came around were the Confederacy of Independent Systems (the Separatists) who fought the Clone Wars against the Galactic Republic, but before that there was also the Sith Empire, which rose and fell at various times during the Old Republic era. As well, the actual predecessor to the Empire was the Republic, which was not one of the bad guys, at least not from a narrative standpoint. I’m not sure how into the canon/Legends you have gotten, but those would be the big ones that came before the Empire. 

~ Jacen 

Would you happen to know of any species (preferably near-human or humanoid ones) whose planets were either allied with the Empire against their will or outright conquered by the Empire? Basically, I’m making an Inquisitor with an “I had no choice but to join them” type of sob story, and I need a species that comes with that.

Well, you’ll be pleased to know that you have many to choose from. Not to mention, after Order 66 many new Inquisitors were former Jedi who chose to join the Empire rather than be killed, so they could really be any species at all. But if you need extra incentive, or perhaps your character is one of the Force-sensitive children that the Empire went after, here are some planets of origin to chose from, along with the date they were conquered/annexed/forced to join (if known) and the native or majority species if there is one:

Jelucan (11 BBY, assorted species), Kashyyyk (19 BBY, Wookiee), Hargeeva (7 BBY, Human), Garqi (Human), Ando (Aqualish), Caamas (technically joined willingly but was heavily bombarded in 19 BBY as punishment, Caamasi), Ryloth (Twi’lek), Utapau (19 BBY, Utai and Pau’an), Yaga Minor (after 19 BBY, Yagai).

Hopefully one of those works for you!

~ Jacen

Do you think the new republic has a stronghold outside of Hosnian Prime and still exist or were they truly wiped out as Hux stated?

I don’t know whether you’ve seen The Last Jedi yet, so I won’t go into too much detail. The New Republic had a rotating capital, which was Hosnian Prime at the time of its destruction. Due to the demilitarization measures, I doubt they had so much of a “stronghold” as perhaps another world where they could move any surviving government officials and base their operations, though I don’t know what that world might be. Either way, the New Republic was a galaxy-wide government system and couldn’t really be “wiped out” by the destruction of one star system, though it was a severe blow and it was estimated that the Core Worlds would fall to the First Order within weeks of the start of open war. Were you maybe thinking of the Resistance? If so, I will simply say that the Resistance was not truly wiped out by that incident or the subsequent attack on Starkiller Base. But regardless, yes, the New Republic and the Resistance still exist at this point in the trilogy. 

Hope that helps!

~ Jacen

Have there ever been records of a rebellion/new republic/resistance member going to the empire/first order (besides Anakin?)

Well, at least a few Jedi did join the Empire after Order 66, including the Grand Inquisitor, but they’re not really Rebellion. Naturally there are a few named minor characters who defected from the Rebel Alliance, including Nik, Var Narek, and Mar’holt Kisfrel, and logically there should be a wealth of people over the years who left to join with the Empire or First Order. I do also know of some who, in Legends, left the New Republic to join the Yuuzhan Vong (not sure if that’s helpful or not). Right now no examples of major characters are coming to mind, but the answer to your question would be yes, there are records of Rebellion, New Republic or Resistance members leaving to join the Empire or First Order. 

~ Jacen

I always wondered about relativity’s effect in the Star Wars galaxy, especially since the characters would age differently in lightspeed and traveling on ships than on planets. Also, wouldn’t time pass differently? Do they bend spacetime rules to have events happen in timely manners/ without much time lost?

We have to suspend disbelief a little bit here, but essentially relativity in the Star Wars universe is supposed to work much the same as in real life. The reason why people don’t age or experience time differently in hyperspace when compared to the rest of the universe is that the hyperdrive uses relativistic shielding to counteract the time dilation. In cases where this shielding has malfunctioned, a journey that appears to the passengers to be only a short jump could take centuries in reality, causing them to appear to travel in time. And we have to keep in mind that jumping to hyperspace in Star Wars is treated as entering another dimension, so it’ll be a little different.

~ Jacen

How did the empire control the holonet? I read that the empire used to control messages sent back and forth. If that was the case, do you imagine that propaganda was king?

The Empire basically shut down a large portion of the network and restricted and monitored the rest, meaning that people had great difficulty communicating anything the Empire didn’t want them to. From 19 BBY onward, they really didn’t use it for much else except military communications and propaganda, so yes, it definitely was. 

~ Jacen