Welcome to BP @Javier Sanchez You have come to the right place to get as much knowledge and actionable items to get yourself going.

If you are true partners and upon success, intend to repeat this, you should form an entity together with an operating agreement that spells out each and every soecific item (responsibilities, tasks, money, what happens in case if death, etc. as far as thevowner carried financing, have your attorney draft up a note and deed of trust.

@Muz Khan lots of items in your post so I will try to handle them one at a time here:If you find a HML that doesn't lend to first timers then keep shopping.  

I would show him an itemized list of exactly what my offer is what it is and let him try to argue with it.My $0.02 ...

What items are in your Monthly Operating Expense total? 

Many of our items are brand new, so you can't compare old things to new things.

:https://www.biggerpockets.com/forums/52/topics/680...Without providing a laundry list, I think the theme is to tackle the wear points and troubleshoot the individual unit.For example, start at the door (door mat to catch debris, good functioning new lock, perfect close and open, door stop) and work through each room with that level of detail ( example: Bathroom: new shower curtain, bath mat, caulk, new toilet flapper or overhaul kit inside, strong towel bars, etc.)I would focus first on the low cost items that can prevent larger problems (your doorstop type theme) and then also evaluate any larger item close to the end of its useful life, especially if showing signs of problems (be it hot water heater, worn flooring, or an appliance). 

Here’s what I mean:If you are using a Schedule C in your personal tax returns there are 4 important items to be aware of when a bank calculates your income.Schedule CDepreciation (Line 13/14) – can be added BACK as income Business Use of Home (Line 30) – can be added BACK as incomeVehicle Miles (Line 44A) – can be added BACK as incomeUn-allowed Meals and Entertainment (Line 24B) – is subtracted FROM your incomeSo if your Schedule C taxable income is $0 (line 31) but your depreciation is $10,000 then your actual income is $10,000!

Ok, painting is fairly cheap and easy, but what about more expensive items like carpeting, refinishing hardwood floors, maybe new kitchen countertops, etc?  

But that is no different if it was your own house and you were itemizing.