I'd recommend iOS standards unless you really need to break from convention.  Standard iOS expectation is that you always have a back / up-level nav in the upper left corner. If you put 2 nav icons side-by-side in the upper left (Hamburger and Back Nav) that makes them both less usable and creates challenges - which is the one on the left most side?  Your #2 is the most common implementation.  Do users need to get back to the top most menu frequently enough to require having the hamburger nav on all screens? Then consider...

iOS standards also call for the use of the Tab Bar across the bottom - it is an option if you have a small (7) number of items in your nav (though it does persistently take up screen real-estate so isn't ideal unless the user needs to quickly access a few key screens).  

The big question for any use of Hamburger Menus is... what are you putting in there?  @Majo0od incorrectly states the reasons why hamburger menus are problematic.  Hamburger menus have been being maligned considerably lately and most of the critiques have zero to do with user experience.  List Menus (Hamburger Menus) work great when they provide a consistent list of items clearly delineated.  The majority of user testing with List Menus shows that users very easily understand what they are and often go there to find stuff if the thing they're looking for isn't obvious elsewhere on the screen.  This has led to some bad practice among designers who started tossing everything in there - this leads to a garbage pile of items which makes it difficult for users to find what they're looking for or to know what to expect on subsequent visits to that menu.  A similar List Menu metaphor used all over both iOS and Android is 3 dots on the right (doesn't look like a hamburger so it isn't as maligned but has identical problems when not used consistently).  This is usually used to show a contextual list based on where the user is rather than an omnipresent top left list menu. Going back to my point for this paragraph... what are you using it for? Is it a clearly delineated list of concise items that is contextually relevant to where the user is in the app? Could it be better implemented using a different design pattern? Use the right tool for the job.

iPhone app - Persistent hamburger menu vs last page visited
I've noticed a new mechanic in the 5th edition rules that stands out from the rest. It's called Inspiration.

What is this, what is it good for and how should I as a DM grant it?

It looks like it's simply a way to grant advantage for good role-playing? Is this what it's meant for or does it have more meaning than this?
