I am planning to replace the carpets with luxury vinyl flooring in both the living space shown in the picture and the bedroom.

Which all key figures help developers decide on negotiating terms of JV for development(build and sell).Deal here with one of Landlord is, 52k sq ft plot, Multi Use development possible (Ground + 1 floor parking, 4 floors of commercial space, 14 floors of residential apartments).Owner is not ready to give up on 55 - 45% JV model (55% for Developer, 45% for Land owner + 1.2 mn USD cash).Where as out of 4 prospective Developers, no one is ready to be beyond 34%.

The cost is going to be less than 30k because I will build it myself but obviously the county won't just accept my "random" estimate, they will allow to estimate $123/SF of conditioned space and $22/SF of deck.The floor plan I was planning on building is coming at $37,404 (288 SF floor plan, 90 SF front deck), so my question is : shall I make it smaller to get below that 30k limit ?

This is huge for you as a new person in the space to do it repeatedly and learn from someone that has massive experience. 

But in 1-4 door space and Fin of Am you can get 30 yr am fixed term. 

Below is a chart showing the average reclassification percentages by property type.Apartment Building - 20-40%Conference Center - 25-35%Fitness Center - 22-45%Assisted Living Facility - 22-45%Golf Course - 28-60%Theme Park - 16-22%Grocery Store - 20-45%Hospital - 28-40%Auto-Car Dealership - 29-35%Hotels - 20-40%Research Facility - 22-45%Manufacturing - 20-40%Warehouse - 20-30%Medical Office/Clinic - 22-35%Resort - 25-45%Mixed Use - 20-40%Leasehold Improvements - 20-80%Office Building - 20-30%Retail Strip Mall - 18-40%Winery - 18-25%Restaurant - 20-80%Bank - 30-45%Are there any other types of properties you would like more information on?

We offer it to free for our clients because we know that it seals the deal when people walk through the space.   

Larger square footage may also be dividable in a way to create multiple living spaces.

The new rental has a modern kitchen, new appliances, LVP flooring, new central air, LED lighting, new window, paint, texture, etc.

Start with a small insignificant space to learn what you need to learn (keeping planks from shifting, layouts & cuts, etc).