Um that's in a shower? Why aren't the walls durarock?

HardieBacker cement board is a tile underlayment made for
wet areas like kitchens and bathrooms. This cement-based backer board,
made of 90% Portland cement and sand, resists damage from moisture and
mold and provides excellent tile adhesion. Its formulation and structure
results in the ideal combination of strength, uniform composition and
performance that no other backer board can provide. HardieBacker cement
board was made to be easier to work with so that regardless of how you
cut your board, the result is less debris. HardieBacker cement board's
superior strength and durability delivers a solid foundation for tile
jobs to help protect your work and reputation. James Hardie stands
behind HardieBacker cement board with a limited lifetime product
warranty.

California residents: see
Proposition 65 information

• The Most Preferred Brand of Backer Board by Tile Installers and Contractors
• HardieBacker 500 cement board (0.42 in. thick) is best used for walls, ceilings and floors
• Made better - The 90%
  Portland cement and sand formulation provides a solid foundation for
  your tile with up to 3 times the compressive strength of competitive
  board
• Installs better - cuts cleaner for tighter seam lines and less debris
• Performs better - unique formulation delivers a product with outstanding resistance to moisture and mold
• Score and snap the board
  by making 2-3 passes with a utility knife or a carbide tipped blade,
  place one hand and knee firmly along the score line, then use the
  opposite hand to pull the board up
• Cut HardieBacker cement
  board with snapper shears instead of a grinder for the same clean, sharp
  edges for straight seam lines while significantly reducing the amount
  of dust in your work environment
• Limited lifetime product warranty
• Non-combustible

What are you using for waterproofing?

Judging by your photo poly was not installed behind the backer board for waterproofing. Have you selected which waterproofing method to use or are you under the assumption that the Hardi board is waterproof. Which it is not.

At this time I have a Shluter/Kerdi shower pan kit. I was planning on using Redgard on the walls. Its a large shower 7' by 7' so using Redgard would help keep the cost down. That was my thinking anyways.

You are right Hardi is not water proof . That is why after much research I felt comfortable using Redgard. However in there videos they do show using it over dry wall which I was not comfortable with. My main concern is how to make sure I get these windows sealed. Any suggestion would be appreciated. Thanks

On the windows you don't have a lot of room to work with. Maybe use some of that metal tile finishing strip and some caulk. In my bathroom I have vinyl windows over the bath with about a 3" return to the wall. The sill and sides were Durarocked, taped and covered with thinset before Hydroban waterproofing. The small gap between the Durarock and the window was filled with Hydroban and it was painted onto the window to make a seal. Then marble jams and a sill went on with all the joints getting caulk. the sill is obviously tilted towards the bath.

Thanks for the suggestion. Couldn't sleep last night thinking about this. So I got this morning and cut them out and am now having them flush with tile

Creative Eastern, should he tape, thinset the tape, then paint with Redguard, all around the wood and wall board, up to the silicone?

Oh, I see that Jeff Meeks mentions something like this in his post.