I am assuming these two are part of the same plan. I'm a bit concerned that this method will actively lock out people who are not paying - because what I like the most about the support program as it is now, is that it doesn't actively lock anyone out. You're not punished for not paying, but you ARE rewarded if you do, with earlier episodes and so on so forth.
Working through Apple and Google's in-app things might be a good idea, I honestly have no idea how they function, as long as you can maintain the key functionality of what's the current support program. People like what they see and pay for earlier access and other bonuses. What people will NOT do is to pay for content they don't already know and like.
As for Patreon, I would avoid associating with them - Tapastic has a good reputation, Patreon doesn't. Crowfunding in itself was never meant to be used as a sustainable income, it's meant to be the starting point of a project, not a livelihood.
As for novels, as an author myself, the concept in itself isn't bad - I would've been interested. If you'd kept the support program model. Without something like it, I may as well go self publish on Amazon and market myself on my own.
Professional writing and how you write a novel is a bit different from how a lot of comics are made, the process is less free, there's not as much room to improvise. A novel has to be a finished project from the very first chapter published, the language used in the book has to be consistent, it's harder to keep consistence in written form than in comic form, because in comics, sure, your style might evolve and that'll be great, but when you read a novel, you need the same language to be present through the whole thing.
I mean, sure, there are people who publish fanfictions and the like on the go - but that's a very different medium from actual novels (nothing bad about fanfictions, one of the best stories I ever read in any genre was a fanfic).
I guess what I'm trying to say is, if I put effort into writing, editing and perfecting an entire novel, what about Tapastic's concept for publishing would make it a preferable platform?
Something I will say is that I would never use Patreon for a novel. Not in my wildest dreams. I'd sooner choose Amazon and publish for Kindle. Would that be compatible with Tapastic's system? I just don't know.