This seems more like a Facebook wall where you approve each post. The design looks good from what I can tell, not sure it you have apps or if this is open source, but in terms of making a company out of this it seems like little value compared to free alternatives that already exist. With email, I can already create white lists. Also, what is to stop a group of accounts from spamming someone with requests?

Mastodon let's you filter people and block them as well, and there are plenty of similar apps that provide actions to create and filter groups of conversations.