Good questions, and lots of "it depends" answers...but I'll try to give my perspective.
1. As a BI & Analytics Consultant, I see many companies hire somewhat technical people (analysts) within their business units to try and bridge the gap with IT. You'd think that we would have figured out how to get IT and Business to work together in harmony by now, but that's unfortunately not the case in many organizations and the business gets frustrated with IT's lack of (and slow) response to solve real business problems. Generally speaking, it would be the Analyst who asks the questions and IT to provide the technical answers, but it varies greatly and an Analyst who can ask the right questions and bridge the gap successfully with enough technical knowledge is worth a ton. From what I've seen, most companies expect some level of reporting capability from Analysts. But the more technical knowledge you have, the more value you would bring as you would not be reliant on IT for everything.
2. Yes, I see this very often. Power BI is very intuitive and easy to use, but an end user without the necessary technical skills are just not able to develop enterprise-ready data models. That is still very much a technical skill, and a lot of my Power BI work as a consultant is to businesses create data models that can scale and be shared with many people.
3. In my experience, the ability to create a star-schema data model (which is the most effective data model for OLAP analysis) is something that very few Analysts have. Understanding the source data and systems would be another.
4. This really ties into my previous two answers. From what I've seen, most Analysts create single flat table data models. This might be ok for your one-off initiative, but doesn't scale when the model becomes complex or contains a lot of data. At least from a Microsoft perspective (Power BI), a star-schema is still a best practice. Dimensional data modelling skills would add to your value exponentially, and this is the message I give to every Analyst I ever speak to.
5. There are many resources out there, and you being on this site is a good start. Here's a few others I can recommend (some of them have video content):