aivihc

thanks for the tip @jlmphotos 

If I have to travel super light but still need to backup my photos, I have a 500 gb SSD in an USB powered case and use my RAVPower Wireless Card Reader to transfer the data around. That is usually sufficient for quite a long time for me and doesn't require too much space.
 
As for SD cards, I always have 3 high speed (80+ mbps) 64 GB cards along 2 slower class 10 micro SD cards with converters at 32 GB each.
 
All that is stored in a Peak Design Pouch along a couple of USB cables, a Fuji traveler USB charger for the batteries, a couple of extra batteries and a Pocket WiFi and a 2 ports wall charger.

I typically never go higher then 32, but I do have a few 64s.  I just take my full wallet full of cards on a trip.  I don't erase them until you get home and get them backed up, and use a wireless drive to back them up while out (Card plus Wireless = 2 copies).  That's my set up...

I use various cards in range from 16G to 64G, but my travel starts with fastest cards - that's help to save battery a bit. Yes. 
Then I use my "regular speed" cards. Slow cards are last in my queue.

To me I like to "spread the wealth".  Having large 128GB cards, even 64G is too many eggs in one basket.  In my gear I have a split of 32G and 16G SD cards.  I can take a total of 8,943 images shooting JPEG + Raw.  If I lose a card, or it's somehow damaged, or the camera is stolen, I only lose either 891, or 480 (approx) images on the card depending if they were 32 or 16G.  Also, Once the card is full and back in my card wallet the card wallet is NO LONGER KEPT with the cameras.  The card wallet is on my person wherever I go, at anytime.  If the camera gear is stolen, I still have my images.  
That's my story and I'm sticking to it.

12mm + 56mm would be my take.
 
12 + 23 + 56 combo should be a really nice suite of lenses for your kind of photography.

I use the 16-55 with an XT-1 for flash, portraiture and event photography with 10-24 and 55-200;  but use an XT-10 with 18-135 for travel. I had the primes and swapped for 16-55 which as noted is not OIS but covers 80% of needs. Also had the 18-55 OIS for travel but felt I needed a bit more reach and carry only one lens for travel.

In a single lens the 16-55 seems the best bet, its fairly wide, fairly fast at 2.8 and covers a good range. Has great IQ, weather sealing etc.
 
That said I'd probably like a 16 and 56 to add to the 23 due to the size and weight of the 16-55.