So far I have only tried to write one novel (which failed). If I had one piece of advice I'd give you, it's to not workshop your novel while you write it. Some people can do this, but it killed my novel for me. For my second try (which I will be starting soon, hopefully), I will write the first draft, then workshop it. That way I don't get hung up fixing things and redrafting my first 10 chapters like I did last time.
Someone gave me some good advice (that I will heed next time). They said to go ahead and workshop the first few chapters to see if the tone and idea of the story works. If it does, then write it on your own, then come back and workshop it. I'm a perfectionist, so I think that's the path I'm going to have to take. If right now you have a driving, undeniable urge to re-write the last two chapters according to the feedback you just got, well, I'd recommend writing the rest of it privately. Your theme is great. Your characters work. Just write it, then re-work it. I plan on sending mine to family and whatnot for moral support, but not critical feedback.