The best thing you can do is make sure you use a Mobile UI Framework like KendoUI or jQuery Mobile.
They are both built from the ground up to support css responsive design so they are huge time-savers.
Luckily Icenium comes with built-in templates for both so you can get up and running pretty quickly with your mobile-hybrid app.
Regarding the device orientation lock. You can specify that on your project properties on Icenium
Hope this helps.