eBay and Craigslist finds

A very big gamble in my view, as he'd stated that his LBS had tried to remove it and failed.

I hope they didn't damage the frame and you have some joy in getting out, the shame is that the seatpost will be ruined and you'll struggle to find another to replace it.

could have been 'local childrens prams and bicycle store' or halfordsesque place

stick a saddle on it and find someone strong to twist it off or hammer(mallet) it off