I am an architect and designer with experience in the short term and I know the Catskills area. contact me if you need some help, I will be happy to help.

I am a wholesaler and a carpenter myself so I know what comes with the building part, but I am not sure how to go about starting the process such as finding the land, average or rough amount we can or will spend on permits, architect etc...Any good app or websites to find land/properties will help as well.

Since this would only be breaking the floor an inch or so down (to reach the wood from the old staircase) I was wondering if this would be a project that would need the basement digging permit/architect/engineer?

I am a architect/engineer.

Then find the property and your design team (can just be the architect or engineer at first). 

I am helping my architect brother raise private funds from family to start developing vacant lots into new single family homes that he will designm.

I work in partnership with an internationally recognized Architect also based in Toronto who previously lived in San-Francisco and is registered in-state and previously worked for SOM before doing her post graduate in Architecture at Harvard.

When doing a new deal do you usually assume a cost per square footage and costs for permits, working with the city, architect, lawyers, etc?

So make sure your architect knows their zoning!  

When building an ADU do you have to use an architect to make the plans or can the builder do that?