Internal lateral process taking super long - would love some advice

Hey monkeys - quite a unique situation and I would really appreciate some advice / thoughts as I figure out next steps. 

I interviewed for an internal lateral role c.6 months ago and was put on a waitlist after final round. The staffer informally told me the team wanted to give me an offer but a senior pushed a random candidate through so I would be next pending headcount. 

Then c.2 months ago, I got a call from the staffer asking if I was still interested in joining and he gave me a verbal offer confirming there would be no more interviews or anything else ahead of joining - just the headcount approvals. 

I then got an email a week later saying the global head of the team wanted to have a quick catch up with me and we basically just spoke about the team and the market for 30 mins. He told me to stay on top of the staffer to push the process along so I think I got the green light. 

As of today, I just caught up again with the staffer and he told me they are still working through approvals (will take another 3 weeks or so) and he mentioned that they had interviewed another dude for the role but they didn't like him - basically warning me that they may find someone else in the meantime. 

So basically I get the feeling I'm not really likely to ever see a written offer as of now. It's taking super long, and the team seems to be interviewing others as well (at least the staffer is a good dude and let me know rather than dragging me along totally in the dark). 

I'm now looking externally for lateral opportunities and am getting some traction. What are the odds I actually end up moving internally and what can / should I do to try to improve the situation or push things along?