I don't think it will be as simple as trying to just undo what the last owner did; you're going to need legal descriptions of each lot and that generally requires a survey. 

I was able to get the HOA to approve the addition of another small dock right behind my house with a 23 x 8 foot slip 2 years ago.

@Aubrey Adams-Thanks for the post / question -I would recommend developing a hypothetical plan  ( purchase price / loan amt needed ) and get pre approved ..this process is free and it will help get you organized and also to educate you  in many ways ..if you never end up buying - no worries and no costs have been wasted 

@Jessica Heller- contact  several  lenders on the  same  day - provide them  with the  same criteria -  get  some  quotes and ask the  questions you have  ...compare the date and the feedback received and then make a  decison on  starting the pre approval process 

Fill out both medical and legal power of attorneys.  

Rehab the house while you get lot split approved.

Get pre-approved for a buy and hold loan- It could be multifamily, single family.... depends on the market3.

Prioritize due diligence, including a thorough property inspection, financial analysis, and legal review.

The lender approved it no problem with 20% down. 

An LLC creates a legal separation between you and the property, so if something goes wrong—like a lawsuit or debts related to the property—your personal savings, home, and other assets are shielded.