One SQL Server. One SSIS. Two versions of DTExec.exe?
No.

SSD-BI edition is now a free download. That license allows you to develop SSIS packages that target a 2012 SQL Server Integration Services machine. That license does not grant you the right to use it for production-like usage. 

Furthermore, when you try to run a package from the command line, you're going to be met with an exception stating that ~ this is only for invocation through Visual Studio. The only way to make that go away is by installing the SQL Server Integration Services Service which is part of the 2012/2014 installation media.