Those portable chargers for your NiMH AA/AAA are nice. And if you run into trouble with your rechargeables, you can always go to alkaline while you get the rechargeable situation sorted out.
Since you asked for suggestions, I suggest a Garmin eTrex 20 or eTrex30, and your choice of cameras. I’ll admit it has gotten hard to find pocket cameras that take standard (AA or AAA) batteries, so for them the spare batteries and managing charge on them is of greater importance. I like the Nikon Coolpix and Canon Powershot lines of pocket cameras. Their optics are vastly superior to what you’ll find on a cellphone. Unfortunately, they’ve all gone to the little square lithium batteries.
As to the phone or tablet ... you’ll find the tablet easier for editing video. You’ll find the phone more flexible for getting on a network. What’s most important?
I’ve spent too much time (professionally and recreationally) in the boonies to trust ANY device that I can’t swap the batteries on, and for which I can’t get spares. I’m going to spend two weeks in the desert next month. I won’t be counting on my phone (Galaxy S6) to be anything other than dead weight most of the time. ALL of my “mission critical” devices will be of the sort dedicated to the particular task.