I don't do enough transactions like a realtor to warrant a monthly subscription.

A subscription to DocuSign is probably too expensive.

Do we have to buy subscriptions ($50~100/month)?

In order to wholesale with a license the most important thing is to ensure the seller and buyer sign the proper disclosure forms notifying them that their unrepresented ie. you’re not representing them in the role of their agent.I do agree getting your license presents more opportunities however their are fees as a licensee you have to pay (mls access subscription, E&O insurance, transaction fees to broker) just keep this in mind.Lastly, some brokers frown upon wholesaling with a license so make sure the broker you hang your license with is ok with. 

I would recommend quickbooks and then up your subscription to the level where you can track expense by "class".

Many investment funds work with the LP structure where the LP is a capital provider and the GP is the manager.Every company can have it's own different structure and to understand that you would really need to understand what is written inside the operating agreement or if the manager is using the company as a fund, you would to read the subscription documents.If you add some more detail, we might be able to also add some more insight for you.

Is the monthly subscription worth it or do you all deal with maintenance issues as they come up?

The intercom is to communicate with the mail room and guests, and allow each unit to release the electric door lockI am not looking for a subscription with an annual fee.

Definitely want to confirm the attorney you work with has experience in creating Operating Agreements, PPM, and Subscription Agreements. 

And you should have a website because some of those people will wander over and book direct. you should use a channel manager avoid double bookings and to provide the website. ownerreservations and smoobu and lodgify for example will give you a website as part of your subscription. and being on all the websites you can diversify such as higher prices and or longer minimum stays.