Celtic knot work sounds beautiful!
Start browsing the most favorited cakes on this website, bride magazines, martha stewart weddings, Pinterest (yeah! I said it! Pinterest!!), fashion magazines, runway collections, scrapbooking supplies.
If cake pops are not an important part of your business, I wouldn't make them. To me, they're not quick or Simple. They're a pain in the butt. And the business you might drum up from this is going to be people looking for cheap cake pops.
I agree with previous posters: full price items that are the actual things you want to promote and sell in your business or free samples.
I've never heard of the product you mentioned, but stabilized whipped cream is just what it says. There are several ways to stabilize it so it wont weep AS FAST. it doesn't make it last forever. You can use piping gel or gelatine to stabilize and cover cakes with it. I think most things I've seen say use within 3 days, and of course you still keep it refrigerated.
This will always be a balancing act. What were the times they wanted and why couldn't you meet them then? If this was a one-off occurrence, then forget it. If it's happening a lot and affecting your business, maybe you need to rethink your priorities.
This is not a spray, but it is edible. I have the gold and like it pretty well.
Are you tinting your fondant before spraying with the wilton stuff? I make gray fondant and spray it silver. I did some cookies that way. They are not super shiny though.