It looks like you are getting very close now. So your recordset on the second page is selecting all from the people table. This is rite. The idea is that with DataAssist Search applied to the recordset it should be filtered on the list of id's that are passed to it. It sounds like you have configured the search correctly for the column lookup, but what have you specified for the type setting? You need to make sure this is set to list to handle multiple values that are passed from your target list on page 1. If you are posting just a single value then the value type search should work. There is one last thing you need to ensure you are configuring with DataAssist. The default WHERE clause should be set to something that will never be true, like 1 = 0.
Once the DA Search is correctly configured the recordset on this page will be filtered based on the values from your target list on the first page. So only users that have been selected will be in the recordset. You can then apply Universal Email and do the recordset loop, it will only send to the users in the recordset. To get the name in the message just use the bindings for the recordset and select the name column or any other value and bind it.