Can I include my client in the messaging thread, or have all three of us, broker, client, and lender, in one place?

You control how visible each deal is, so client involvement is your call. When you create a deal you can keep it visible only to your team or include the client, and if you include them they get their own portal access where they can see progress, upload documents, and message you directly. Client messaging is a direct line between you and your client, separate from your lender communication, which keeps you in the quarterback role rather than putting the lender and client in the same thread. So the practical setup is broker-to-client messaging in the portal and broker-to-lender messaging in the deal room, with you connecting the two. If you'd rather work fully white glove and keep the client out of it, you can manage everything yourself and loop them in when you're ready.