I agree 100% that you need to be working with a tax lawyer and CPA that specializes in this area, otherwise you greatly risk filing this incorrectly and subjecting yourself to substantial penalties.

The fees you were quoted are extremely low for a case like this which makes me suspect that they either haven't done a case like this before and/or they don't know what it's all going to take to correct it. You're likely looking at some reporting complications due to the foreign mutual funds and it's important to determine whether the rental property is considered a business entity or directly owned by yourself in the eyes of the US.

The most important thing you need to do is find someone you trust as well as someone that knows what they're doing. This is an area I specialize in as a tax accountant and I have lawyer contacts in the south that specialize in this area of practice. However, I'm not sure we would be the best fit as our fees are likely too high for you. Nevertheless, if you'd like to PM me to discuss more, please feel free.