I have a fiberglass pool that I installed myself. My pool has a raised concrete deck around 3/4 of it.. The deck is pretty solid and has been down for 5-6 years. It terminates about 1/4" below the rim of the pool and angles down into yard. I was looking to improve the look of the pool and really like flagstone and cantilevered edges. I have a quarry nearby where I can get it and was thinking about doing a cantilevered flagstone deck that would extend over the lip of the pool by about 1-2". Originally I was thinking that I would just pry up each of of the concrete pads that I poured around the pool, and pour new pads flush with the pool and flagstone over them. But after reflection, it seem a waste to destroy/remove the pads there already just to pour new ones. So I have questions:

A. Can I mortar down flagstone over the existing pads without removing them? They are currently textured concrete (cobblestone pattern) painted with a Xylene based cement paint. Would they need to be treated to have the mortar stick to them?

B. I might have to raise some portions of the existing deck before applying flagstone. Can I pour a thin layer of some type of special cement mix over the existing deck too work from? Should I just do this to the whole deck to make it consistent? If I can do this, what special mortar would I use? Any special prep?

C. How would one prep the lip of the pool to adhere better to the flagstone. I was thinking drill holes in the lip, sand it down, and comb epoxy over it to give it texture. After the flagstone is on should I caulk underneath the lip where the flagstone meets the fiberglass?

D. Other other advice?

I am planning to build a cinder block frame around the side that is currently wood decking and then filling it with compacted road base and them doing the flagstone over that. Here some pics as well

Current deck. It might look like individual stones but it is solid with a patten pressed into it.

Here is the look that I am going for: