1. Domain name clearly states what the niche is about, it's also clear from the backlinks what the niche is about. Yet you plan to re-purpose the domain about something completely different.
2. Domain name is somewhat ambiguous/generic and has primarily branded links, making it less clear what the site is about. However, while tier 1 (links to money site) is focused on your niche (obviously), tier 2 (backlinks to expired domain) are coming from sites about a niche that you're not planning on entering.
3. What is the importance of the above in relation to the competitiveness of the terms you are targeting?
Of course, you could also build links yourself to an expired domain to add more relevance, but anyway, thoughts, guys?
As is always the case in this game, one statement/question leads to another, so:
Irrelevant links still seem to be working now, but it would be hard to doubt the added power of relevant links throughout all your tiers now and in the future as Google gets smarter.
It's completely normal for non-internet marketers to not have the faintest idea about PBNs and expired domains, so will purchase a domain they like the sound of and start a website about a completely different niche. You could argue that this would stop Google from putting too much emphasis on relevancy. But then again, why would Google care?
Small business owners are the ones who get caught in the crossfire and tend to be hit the worst by updates anyway. In fact (conspiracy incoming), it wouldn't be beyond the realm of possibility to assume that Google love it when this happens. Internet marketers can and will usually adapt, the small business owner, however, will move to Adwords and line Google's pockets.
Please don't respond about what works now (thousands of blog comments used to work like a charm), but rather the direction you think SEO, and more specifically PBNs/expired domains, will go in.