With or without variance you'll need to submit plans to L&I for permits so I'd put in 10k for architects & permitting fees on the low end.

Check to see if you have to install any manholes, fire hydrants, curb, gutter, sidewalks, street signs, street lighting any specific street design or access requirements, Check DOT requirements for access, stop lights and permits, traffic studies, DWQ requirements for permits, permit fees and time frames.Once you have an idea of what you can build and what is required in terms of permitting and infrastructure you want to talk to some civil engineers, architects and commercial general contractors that do the type of projects and build the type of buildings you want to build so you can get an idea of costs, time frame and requirements.

I know that an architect will be involved as well as all the necessary changes to plumbing, electric, heating and meters.

Project managers for flips or new construction should not only deal with the GC and the subs making sure they work in a timely fashion, show up, and do quality control, they should also be running errands and even have knowledge and experience in selecting finishes to maximize your profit margin, i.e. picking the $200 light fixture that gives the appearance of a $500 fixture, etc.They should also assist and coordinate with permits, the architect (if additions and/or new construction), the utility companies, the stager, the clean up crew, etc.

Your architect should have a good understanding of what the market dictates as far as layout and bedrooms, etc.

I need an architect to draw up renderings.

The world needs more Architects.

I am an architect in the city who has experience taking projects like this through the appeals process (not selling my services, just giving context).

We now have a complete fire sprinkler system installed, all units have 2 stair exits down & all units now have adequate egress windows installed.Took me about 18 months to complete it to code & had to get it signed off as compliant by our commercial architect, the bldg insp & the fire chief. 

The ADU laws (which again change in January - mostly for the better) make it very easy to convert a garage or "rec room" to a legal ADU, you just need to follow the guidelines which any competent contractor or architect can assist you with.