Hi all, recently purchased a home that was build in 2015 and unfortunately the builder and architect had zero understanding of roof ventilation/condensation which caused the assembly to build up lots of condensation which I recently discovered.

A few points on the assembly: 
1. Failure is only on the north side of the roof.
2. Whole roof was wrapped with Ice and Water Shiled.
3. There are steel ridge beams in 2 areas of the ridge. Other ridges are lumber.
4. Home is in Southern California Zone 3B

Here are some photos of the failure: https://photos.app.goo.gl/wQW6a9KKSeZZ1Kfk9

My plan for repair is to remediate the mold, replace all the corroded joist hangers and nails, replace any damaged plywood, redo the roof, and install 2″ closed cell spray foam on the underside of the roof deck with batt for the remainder of the 8″ rafter bays. 

My issue is with the steel ridge beams and the beam column caps. 

Questions are as follows: 

1. There is about a 2″ gap under the steel ridge beam, as shown in this photo (https://photos.app.goo.gl/ycRRiPatGjMxEPwK7) that I can put spray foam. Code only requires R10 spray foam in my area so would this be enough or should I fur down the ceiling to encapsulate the beam more fully?

2. The beam column caps are flush with the underside of the wood ridge beams, as shown in these photos (https://photos.app.goo.gl/ogyRWbyPKRxukfph7). Would it be okay if the column caps are not spray foamed, or should I fur down the ceiling to encapsulate the column caps as well? 

3. Are areas with double framing susceptible to moisture intrusion since I can’t fit spray foam there? How do people deal with double framing and spray foam? Caulk the gaps as best as possible?

Thank you for reading and any input.