No, the fragment of XML you showed above is number threads in JBoss EAP, those do not correlate to the number of data sources. Each data source configuration, under "data sources" subsystem where you define the URL, username, password etc, you can also define the min and max number connections to the source database you create in that connection pool. Here you define as many you want, obviously you need to be aware about what is feasible for the given VM and your environment. Saying I want 2000 connections when your Oracle instance only supports or capable of 200 is not going to help.
As per how many connections that Teiid uses is dictated by Teiid query plan based on the query. Typically it is one connection per datasource/query, and possibly one thread for datasource and one for processing. But both connections and threads are returned to pool when they are idle are free.