Hi,

1.Would you tell me if the steps I applied in writing out adjectives are correct or not?

 a stone-accented conversation piece -- I don't know what a "conversation piece" is but I think it is something you sit on or use when having conversation with others.
First, I think 'conversation piece' goes together.
The "stone-accented' needed to be hyphenated since it goes together - meant to be one compound adjective (if that is the right term).
So, overall, the phrase looks to be correct.

I think you can add something like 'thoroughly stained' if you need to, making it:

a thoroughly-stained, stone-accented conversation piece

Normally, I think you wouldn't hyphenate 'thorougly stained' if used in front of a noun but this is a different case:
eg,
a thoroughly stained (conversation) piece 

2. Would you use two (or possibly more?? - highly  doubtful in its possibility though) adjectives that end in "-al"? How would you rewrite it?

a organizational procedural document

Thank you.