I own a mobile home that I rent out and I am looking to make my first MFH purchase this upcoming year to house hack. 

Quote from @Spencer Elliott: Long story short, land is on loan and I’m purchasing a manufactured lot as a temporary home/future ADU to my final build.

In addition, since the rule changes, it seems like many agents are delaying the whole conversation until the very last minute when the buyer has little or no opportunity to object, research, or think about what they are agreeing to, without risking losing the home they just decided to offer on.

Only if things go very, very badly, and you are in the tiny fraction of loans that default do you... go back to where you are right now, having "purchased" (foreclosed) on a property for 65% to 70% of what you believe it's worth (otherwise, you wouldn't lend 65% to 70% LTV). 

I ran every scenario of tackling this purchase myself.

And as investors we should know this, but always anticipate higher costs and longer waits.EXAMPLE Breakdown of Costs:Plan Purchase: $1,500Permitting Fees: $2,500-7,500Site Preparation (grading, utilities, foundation): $20,000–$30,000ADUs require separate utility connections for water, electricity, and sewer but you can tap into existing utilities at the primary houseIn Raleigh you CANNOT split lots fee simple, so setting up completely separate utilities would not allow you to section off the ADU as of nowYour ADU must be on a permanent foundation (no wheels, no ability to move the structure)Construction (labor and materials): $100,000–$150,000Low-grade: $150–$180/sq ft averageMid-grade: $180–$220/sq ft averageHigh-end: $220–$250/sq ft averageLandscaping/Finishing Touches: $5,000Total Estimated Cost: $125,000–$200,000You could easily spend $200k+ with super end high finishes, custom designs, complicated sitework, adding a second story or more sqft, etc.

Did you expect it to be that lucrative when you made the purchase?

Quote from @Joey Backs: Quote from @Erik Estrada: Are you planning to purchase in an investment property or primary residence?

Purchase price: $270,000 We bought our primary residence in 2012.

There is a filtration (basic ) in thee garage that came with the house when I purchased, but the filter gets rusty in about 5 days.