Its architecture and housing in areas is phenomenal and dense.  

I love architecture and building.  

But taking it from the architectural drawings to occupation on our build (2 Bedroom) should take about 5 to 7 months. 

First off, I work for an architecture firm in North Plainfield, New Jersey.

The type of repairs also varies based on the loan type, here's some information pasted from (not my site) https://themortgagereports.com/18228/which-fha-203k-loan-home-construction-standard-streamlineThis is the work which is allowed via the FHA 203k Limited: Repair/replacement of roofs, gutters and downspoutsRepair/replacement/upgrade of existing HVAC systemsRepair/replacement/upgrade of plumbing and electrical systemsRepair/replacement of existing flooringMinor remodeling which does not involve structural repairsExterior and interior paintingWeatherization of windows and doors, insulation, weather stripping.Purchase and installation of appliancesImprovements for accessibility for persons with disabilitiesLead-based paint stabilization or abatement of lead-based paint hazardsRepair, replacement or the addition of exterior decks, patios, and porchesBasement remodeling which does not involve structural repairsBasement waterproofingWindow and door replacement and exterior siding replacementWell or septic system repair or replacementAnd, this is the work allowed via the FHA 203k Standard: Major rehabilitation, such as the relocation of a load-bearing wallNew construction, including room additionsRepair of structural damageRepairs requiring detailed drawings or architectural exhibitsLandscaping or similar “site amenity” improvementAny repair requiring a work schedule longer than three (3) months; or rehabilitation activities that require more than two (2) payments per specialized contractorImprovements that require a plan reviewerImprovements that result in work not starting within 30 days after loan closing; or cause the owner to be displaced from the property for more than 30 days during the time the rehabilitation work is being conducted

Interior design (unless you mean architectural design) like colors, floors, materials, etc are mostly meant not to turn people off.

The house has nice architectural elements and your updates are lovely. 

This takes Legal (land use attorney) + depth of Architectural experience.

I say this having started in architecture in NYC in 2003 and know dealing with the NYC DOB is an art.

Hire a competent EXPERIENCED Multi-family Architectural firm with an infrastructure (internally and reliable contractor contacts) in place to make the job happen.Step 2.