At the end of one year I paid for an appraisal documented my 20%++ in equity and got my collaterals back.

Next year submit a new increase. 

The amount of permits and how many plans, details and documents is totally under the purview of the Engineer themselves.

Unless there is significant equity in the property 50% LTV may not be enough to payoff the current underlying mortgage.Now here are the exceptions to lift the COB 50% limited LTV restriction:- you inherit the property and it was transferred into your name either via legal award from a domestic partnership/marriage - you have been on title for 24 + months- you took title to the property that was transferred from a partnership or partnership like entity (LLC, LP, etc) that you can document the ownership of 25% or more in- you lived in the property and have been on title for atleast 12 months as a primary residence- you have paid the mortgage for atleast 12 months - or you can demonstrate a relationship with the obligator (domestic partner, relative, family member, etc. )If you qualify for one of the exceptions you are not limited to the 50% max LTV  when considering fannie/freddie conventional cash out refinances on a subject to transaction.

What documentation do I have to do during this 1st part of my acquisition before I do my whole due diligence?

My rent gets paid on time and everything is documented.

“Business equity line of credit: Use Real Estate as Equity” up to $500k, interest only. gather your business and personal tax returns, financial statements, articles of incorporation and other legal documents.”Vectra Bank - ColoVeritex, TX HELOCWebster Bank, CT, RIWAFD Bank.

Update- After dealing with a couple different realtors and submitting offers.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

He is probably drawing up a Quit Claim Deed, which is usually a 1-page document.  95% of what is in a Quit Claim is copy / paste so it shouldn't take that long.