I have never had a problem with all my camera, housing, strobes, arms, and even allen wrenches. They may inspect them by hand, but once they see it is underwater photo equipment they usually just swab test it for explosive residue and let you go on. Just be nice and patient and tell them how nice their uniforms look.
Microsoft Surface Pro and a few USB 3.0 external drives should do. Surface Pro also has Micro SD card reader so that is an option to store backups(may need a few cards) if you want to travel lite. You can probably pick up a Surface Pro 2 or 3 for under $500 now. I have the original Surface Pro and it works fine with Lightroom and Windows 10