Have you checked at Rig-Rite Inc. - Masts, Booms, Spars, Rigging, and Hardware for Sailboats. ?
They seem to be the go-to source for rigging parts.
I have seen a post on this forum where someone did the "pulley only" replacement,
but I don't remember the source. It was in the last 6 months...
I am not familiar with your model boat but I have seen the white spots on my hull in the past.
They are the remains of barnacles which came off when you pressure washed the hull and took the underlying paint with them. I don't think they are the dreaded "boat pox".
The problem is easily fixed...
Guys, it may be a YSB 12, but the YSM 12 was horizontal as well. I had one on my 1979 H30C, but it was raw water cooled and gave up after 20 years and one rebuild. It was less than optimal for the H30C series and I replaced it with a 2GM20F. Solved two problems with that upgrade.
That is water damage with a side of mold.
In my experience repairing panel 3087 is possible. The "How" will require further study and responses from the group. Don't forget to search the archives on this site.
Are panels 3088 and 3089 the underside of 3087?