You're second point is the key.stip wrote:I think it all comes down to how long do you need for the Resistance, armed with the skywalker legend, to rebuild a rebellion out of disaffected elements of the galaxy. 6 months feels a bit abrupt.
It also depends on how the Kylo/Rey relationship (which is the beating heart of this trilogy) goes. Do they want minimal time to have passed, or do they want it to have settled into a certain rhythm
Let's not forget that info travels fast in Star Wars. Those few people on the Falcon aren't the only "Rebels" in the entire galaxy. Just as the First Order is spread out, we know there are others out there elsewhere. And some of them have done this before. There are already pieces in place.
Luke himself tells us that (paraphrasing because I've only seen TLJ once) "Today, the Rebellion is reborn, the war begins and I will not be the last Jedi."
And since TFO is already a stupid military/terrorist organization, and is now led by an angry brat and an incompetent wannabe, I don't think we need a ton of time to pull it all together. But again your second part is for more valuable.