You're right that adding on personal debt will reduce your score but that may be a decent trade off compared to the costs of a hard money loan.   

Then you can refi and pull her money out and return it without adding interest.

Google what it costs locally for a siding contractor or call around and ask what they charge per square(100sqft)If it’s just a few spots you can still calculate your material costs but it will be tough to get your labor cost without someone to look at it.

Going from 1-2 may be a lot easier but when you start adding more than 2 and depending on how high the structure is you get into fire escapes, sprinkler systems etc...The more important question you need to ask is not is there a market for this but can I legally make a 2 unit within the local building codes and keep it financially on point so the project will still be profitable when completed

But it has to be at some sort of discount.You also need to build a buyers list.Something you can start first thing tomorrow to get your feet wet is to jump on craigslist/zillow/kijiji and call every house for rent ad in your area and ask them 2 questions:1.

I would recommend adding your location to your profile - that will make it easier for investors in your region to connect with you.

You can defer taxes on capital gains invested in an OZ until 2026 while reducing your tax basis 15% so it's an added incentive to invest in OZ's. 

Post a new thread here, post on facebook, drive around and call "We buy Houses" signs and ask to be added to their list, post on craigslist, etc. 

Adding another 50% to what think it will cost you to rehab is what I have done - in other words if you still make money at 60k, then your safer. 

So it can be a difficult transition to go from adding value, banking on appreciation to simply placing an investment for cash flow only.