Anyone has other mortgage/finance companies to recommend so I can get a few more quotes to compare?

This will be determined by normal market supply and demand - and researched through property managers, or various online tools that all seek to understand comparable units for rent in any given neighborhood.3 - there is no "right" way to calculate return on investment (roi) - it varies with the property type and your investing goals.

We don’t know any PMCs to recommend in the area mentioned, but since selecting the wrong PMC is usually more harmful than selecting a bad tenant, you might want to read our series about “How to Screen a PMC Better than a Tenant”:https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesWe recommend you get management contracts from several PMCs and compare the services they cover and, more importantly, what they each DO NOT cover.

If flipping, then look at comparable sold homes that also require flood insurance.

Without knowing your rate on a HELOC, there is no way to compare the scenarios.

An appraiser is trying to compare apples to apples and nothing else.

I would then compare my property to those rent ads to help determine a price point, while ensuring that my price point was below the 1 bedroom apartment rentals.

You can show them your analysis or comparable properties to justify the price increase.

I know it's quite a bit more affordable than buildium but supposedly has better usability compared to the new apartments.com version of Cozy. 

Pretty affordable compared some nearby regions.