This is how you do it:
You launch with ONLY one legal specialty, like real estate law for example. You share equity with 5 real estate lawyers, one who mostly handles closings, one who mostly handles landlord/tenant court and so on. Pick their brains individually, for the "easy money" questions they are routinely asked by their existing clients and the most routine services provided to their existing clients and become a high level expert in their respective areas.

Their involvement and your commitment to understanding their business is the first step towards getting your new equity partners to generate your content. For example your new partner that focuses on landlord/tenant court will reveal to you that when a landlord has a non paying tenant, that landlord usually notifies your partner after the delinquent tenant hasn't paid for 75 days, so his challenge is setting expectations for the landlord.
Then he/she will reveal that the first step is for your new partner to assess the landlord's situation and level of documentation/correspondence, followed by a 3-day rent demand letter, a summons and complaint and depending on the circumstances a court date within 45 days in either landlord/tenant court or Supreme Court. And then your new partner has to explain to his landlord client that a judgment is only as valuable as the ability to collect funds, meaning the tenant may not have enough assets to cover the delinquent amount owed. Then of course landlords can get blind sided as tenants fight for a "partial constructive eviction," which is essentially when the tenant says "Hey I would have paid my rent, but the heat was off or the toilets didn't work, so I wasn't able to conduct business, therefor I am entitled to reduced rent."
That is exactly how NYC Real Estate Law works right now and understanding the minutia is key b/c you need to share this information to be perceived as an expert.
You can offer lawyers and their clients meaningful value by analyzing what is being done currently, how it can be improved, but most importantly for right now: How it can be illustrated so you and your lawyer partners can be viewed as the experts you are; This is a great opportunity to illustrate these processes/systems using infographics, so if you don't have a designer, get one. Inform landlords how things work and they will appreciate it immensely, b/c it makes for more accurate reporting and conversations with their partners, more accurate financial projections etc.

Showing people how things work gets them involved and loyal, so I hope this helps.

Btw, who cares about other services that look similar on paper and failed, you are going to be dynamic and offer truly meaningful value and that always wins...

All the best,
Gregg M. Kennelly