Install new walls, or modify the existing panels?

The previous owner of my house installed strand board panels in the living room instead of Sheetrock. I overlooked it, figuring that one day I’d do something about. I prefer not to rip everything out to install Sheetrock. A friend suggested doing a “skim coat” that, if done well, will look like Sheetrock. What’s your opinion on this? Should I tear out and install new walls or go with skim coating?

How do I replace a toilet liner?

I need to replace the foam insulated liner for my toilet or find a model similar to it. My house is 50 years old and has a crawl space, so it has to be insulated to prevent moisture sweating on the tank that drips on the tile.