There is a difference between "some leeway" and going 60%+ over. You are adding 60% to the cost of the book, and that is going to create some rejects.
I found your description of answered and unanswered rather muddled.
The overriding concern is that the reader cannot be disappointed if there is never a sequel. Nobody is going to commit to a sequel unless the first book sells big.
You can certainly leave other mysteries to solve in the world, but if you create "big" questions in the reader's mind and fail to answer them, they won't be looking forward to your sequel that you cannot mention and may never come -- they will just give you a middling review, and then your sales won't be great, and there will be no sequel.
Of course there may not be a first book, because professional readers are much more analytical and less immersed in your story, looking for story problems, and will flag these "big questions" as story problems -- because they won't take any sequels into account, either.
If you've got a good world premise, then you need to trust both professional readers and consumers to realize it can hold more stories, with more characters.
They should be able to tell that the one path your characters followed on this story is just one of many. HSZMV brought up Star Wars -- One of the reasons it was exciting was it introduced a rich and "realistic" world; from the dirty underside Hans Solo introduced us to, to the more natural wild settings and the super-technological and things in-between. The Wild West jumbled up with Jungles and futuristic super-tech cities.
Only at the climax of the first movie (we saw) did Vader go spinning off into space, denying the Rebels total victory, and no big deal was made about that.
There were no big explicit questions spotlighted in that movie, especially about the true identity of Luke's father. I know we didn't know, but Luke did not seem particularly eager to find out; he was satisfied with the claim that Vader killed his father.
Based on your description, I would be concerned that you are spotlighting too many "big questions" for a one-and-only book, and that might prevent it from being published.
The first Star Wars (Episode IV) was not all about defeating the Empire, it was about stopping the Death Star. It had focus, it had to for a first installment.
The same thing goes for your novel. If you want to write a series, your first book must absolutely stand alone. That is all publishers will commit to (for a new author) and all your readers will expect or agree to try.
My advice would be to cut way, way back on the other Big Questions. Focus on one big problem (the Death Star) and solve it. You can leave room for a sequel (Like Vader escaping) without promising a sequel.
Every time you put a spotlight on a big question, you are implicitly promising it will be answered in this episode. At most you should introduce such questions and easily dismiss them -- Like Obi Wan does with a casual lie about Luke's Father, readily accepted by Luke without question.
Trust the publisher and the readers to recognize there is potential in this new world, for sequels.
And maybe, that will help you get to a length, 150K words or so, that a publisher might gamble on.