I'm very happy for you that you chose to address the situation with the best professional advice. I was a bit worried that if you went directly to the IRS without the knowledge of this from proper professionals that you could be trapped into something you didn't need to be in. I take it that if you need a retainer of that size, then there are past filings needed to be done by them. We encountered the same situation and it took 6 years of past filings to cover our previous liabilities for non-willfull lack of filings. They took care of all of this for us, and it was pretty simple - we provided the documentation they needed, and then signed the appropriate forms and they did the filing. I actually hired them again for the 2017 tax year to do the FBAR filings for us (nowhere near the $1500 "cleanup" fees), but just because I don't need to make a mistake in this and the complexities are deep. If you get a chance to review a lot of Anthony Parent's videos on YouTube you will see just how tricky this can be if you don't know what you are doing. I think a simple FBAR is not complex, but often if it is a retirement fund then you have this issue of whether it is a "trust" and then it comes down to whether you have control of it or not. There are different filing requirements for each case and that's why I just chose to pay them to do it. In the end it is peace of mind.
You do start to resent the way that the IRS think they can extort Americans no matter where on this planet they live. There are only a handful of countries that do this - everyone else (incl. my home country of Australia) just do residence based taxation (that is you pay tax where you reside, not both in that local jurisdiction but also to your home country). There's another guy on YouTube you might enjoy "Nomad Capitalist". His name is Andrew Henderson and he is an American who recently renounced his citizenship and chose to live offshore in a number of countries and live the nomadic lifestyle. Not sure if I could do that, but it is interesting to see how someone like him has many passports and does pretty well for himself.
Anyway glad all this information helped you out. I agree - write a blog post about it. These posts live on for a long time and Google will index it and you may just help out the next guy out there too.