Some basic technical questions. Describe a turbine, what instruments make up the T,what instruments use the pitot static system, List off a few ata codes you know. All stuff you should have down lol they are mostly asking questions about you as a person. Answer honestly you can look up STAR interview questions to get a good grasp of understanding how those questions are set up.

The practicals easy basic safety wiring,following instructions, torqueing things down,a few measurements. As for traveling to Houston they will arrange everything from your flight to the hotel ( if needed) and all you have to do is get there on time,my advice is be early. They will provide all the tools you'll need for your testing.

Try and prepare a few questions to ask back that aren't money related. Ask about their company culture, promotions from within etc.