<<I am not paying EE because we don't have a business office fancy for 3 of us yet. We work remote PC and PC.>> Not a legitimate answer.
<<They control their work (IC)>> This is a legitimate answer.
<<All clients (my IC's own clients and my clients)  are paying me>> Why do THEIR clients pay YOU and not THEM if they have their own businesses and clients?

When I started I had one IC, and she took work home. As soon as I brought them in house with my computers and my software they became EEs. It's all about control of them and what they do, where and when they do it.

It's also about income and loss. If they cannot lose money then they are EEs. What happens when a client doesn't pay? Who loses, them or you or both? Do you pay them to work or only if you get paid?

Is this more of a software sharing agreement than an employment agreement? Do you give them 1099s?

<<You are not selling your clients' information. You are still responsible for the clients' identities info according tax law >> If there is a problem, who could get sued by the client, you or the ICs? Who signs as preparer for the IRS to investigate?