ADU in Albany

Hi parents - 

I am looking at possible ADU to my house in Albany. I wonder if anyone here is in Albany and has gone through the ADU process in the past five years, could share their insight or give recommendations? 

Specifically

1. Service provider recommendation
2. General cost advice
3. Project length advice - when will be the best time/month to start? 
4. Any other tips that you could share

Thank you for your helping! Much appreciated.