From your relationships, if you put fields from Investigator List directly on your layout (whether inside a tab control or not), you should see the data from the related Investigator List record. If you used a portal, you'd get the same results--assuming InvestID uniquely identifies one Investigator like your relationships indicate.
If you do not see the data you expect, you'll need to check the relationship and the values in InvestIDfk and InvestID. The current record on your layout would need a value in InvestIDfk that matches a value in InvestID in the Investigator List table. Both InvestID and InvestIDfk should be of the same type when you check their definitions on the Fields tab of Manage | Database.