It's not always easy to predict how easy it is to scrape off the old sealant. I doubt you'll have to get a five-gallon tub of elbow grease for the job, though. On the other hand, a good fresh blade for the razor scraper would not be a bad idea.
Most of these sealants are not recommended for indoor applications for whatever reason, I assume in many cases because of nasty fumes. Plumber's putty is suitable for indoor use, but is not at all appropriate for shower surrounds or similar things as it never really sets up but stays in a clay-like consistency. (It's intended primarily for jobs like setting drains in bathtubs where it's basically enclosed by the parts its sealing.)
For specific details, nothing beats reading all the manufacturer's info on the packages.