Wow! Thank you David, for that additional background and, of course, the much better photos. I like this keris even more now that i can get a good look at it. This is and old and beautiful keris IMHO and you are very fortunate to have become the present custodian of it.
Before i passed these new posts i did add to my first response more info about your hilt. I believe this "pot bellied" style of the planar Nunggak Semi hilt form is referred to as Narada Kandha. Now that i have seen better photos i can confirm that this is an older hilt that was nicely carved.
I can't name this pamor for you, but perhaps someone else will give it a shot. This is an old blade and there has certainly been some loss so it is harder to identify.
You are correct to identify the wrongko as Yogyakarta gayaman form. I am afraid that i do not know the answer to you question about color symbolism for Yogya kraton, but perhaps Alan Maisey might know the answer to this. On the color i see a lot of blue, but i believe that the background/base color of the sunggingan work might be closer to orange.
The pendok is unusual and beautiful. Is it possible that it might be suassa (a low gold content metal) because with the new photos it doesn't look like high gold content and seems have some tarnish which high content gold would not have.
My feeling about gold and silver parts on keris ensembles is that they are meant to shine. I know some collectors worry about removing "precious" patina. Bronze should have patina. Gold should be bright. So if this were in my care i would polish up this pendok and return it to its intended glory.
I am still not completely sure i see the combong. Is it a tiny little hole at the base of the pecetan that i think i can make out in the silhouette photo? If so i have never seen one so small. Interesting.
Thanks so much for sharing your story and this beautiful keris!