@Abdul Azeez, I think that the problem is that you are stacking the deck against yourself trying to do all of these things on your first deal:1) Purchasing the property from an online auction site / bank, which is notoriously tricky even for the experienced investor, due to their proprietary contracts and minimal due diligence period and strict deadlines.2) Working with a new contractor that you haven't used before, or seen their work before, and who may not be used to dealing with investors.3) Trying to get conventional financing on a property that has a short closing time and where the mechanical systems cannot be tested.4) Working on your first deal by yourself instead of partnering with a local investor who can guide you along, or at least a mentor who you can turn to with questions.My advice is to make it easier on yourself by considering buying a property with a standard contract and longer due diligence period, network with local investors who can provide you contractor contacts and also some guidance, and consider using private financing or hard money instead of bank financing.In my opinion, buying from the online auction sites is a more advanced strategy that you can use once you are able to ballpark construction costs yourself and/or you have a trusted contractor you've worked with before and/or you have private financing or hard money set up so you can close fast and/or you can purchase the property without interior access and hope to get lucky in terms of condition (but still buy at a price where you are comfortable doing a full rehab if necessary without losing much money) and/or you are familiar with agreement of sale contracts and closings in your state so you can assess the risks of using the bank's seller-friendly contract.You're already doing the right things by asking questions on this forum, and taking action.  

Your plumbing, electrical, HVAC (includes all mechanicals) can only be pulled by a Master.

A little about my 22 year old self: I graduate May 2017 from North Carolina State University in Mechanical Engineering and a minor in Entrepreneurial Studies.

Off the top of my head I can think of a specialty truck tire place, an auto inspection business, and a lawn mower/small machine repair business.As far as determining price, there's the old standby Loopnet.

I am a mechanical engineer by trade but currently hold a project manager position for small to medium capital projects.

A mechanics lien would not be enforceable......you are a lender/partner, not a contractor.

I am planning on joining forces with a cleaning service called Maidthis, which allows you to auto-sync your airbnb calendar with their cleaning service.

Look for decent pay history on applied for credit like auto loans or prior homes.

The same as having a mechanic check out a used car Before you buy it.

My current hobbies include paintball, auto and tractor restoration, farming and just making things in the shop.