I would consider working with a broker...Most good agents will come to give you consultation for free...and a good one can really help.I own a small coop unit I rent on the UES...used to do it all myself...then met an agent through a common friend who made a great impression very friendly and professional...let him handle the turnover of my apartment and he managed to get me about 15% increase of the monthly rent...When I was doing my open houses I would always got a trickle of people come by...he managed to get 30 people in the door on his 1st open house and 3 application within the week...What I came to realize is that good agents manage to drive much more foot traffic and create a sense of urgency for buyers/renters...In my case he got in a professional photographer who made the place shine...If you DM I can send you his contact...but any good agent from one of the reputable companies in Manhattan can give you a good advice.If your coop allow you to sublet for a year I would seriously consider doing so (If it cover holding cost)...Fall-Winter is the worst season to be on the market...if you can have the place rented and then put it on the market around March-April you might be in a better position...again best to consult few good Manhattan agents.

Tellus: My current solution that lacks web so I have to do everything on a mobile app.

Would start by looking up reputable companies/contractors maybe word of mouth.

Looking for reputable professionals that you’ve had experience with!

They have a web site.Here is a short summary.

My husband and I are starting the planning process to finish our unfinished basement in Roswell, GA (northern suburb of Atlanta) and our plan is to rent it out.We are in need of an architect, preferably one with structural engineering certs because we want to move/open and load bearing wall and would like to only deal with one provider.We plan to do most of the work ourselves, with the wall being the exception but we think we will add somewhere between 1300-1400 sf living space and can rent it for $1200-1400 per month.Looking for reputable architects that you’ve had experience with.

Otherwise look for the city or county property appraiser or tax collectors web page to search by address.

But I imagine that navigating forums and profiles is much easier on the web platform.

However, in order to garner these inbound leads, you'll have to create a trusted and reputable presence with Google and your potential clients. 

The moral issue, as well as the reputational issue, also must be considered.Often, the seller is left with the impression that he has a firm deal.