Hi Jonathan,
I've done a few installations using various techniques and yielding various issues. Shared hosting typically has low memory and code execution timeout limits. I've experienced incompletely decompressed tar.gz files, possibly because the code execution took longer than the timeout, Moodle is a very large file to decompress. Nowadays, for shared hosting, I decompress files on my local machine (no limits!) and then upload them in a cue with an FTP client. Good excuse to go for a coffee break ;)
Re: "I am unclear as to whether the "moodle" folder is sacrosanct for the program to work properly" -- No, the Moodle directory can be named anything you like. Just make sure that the file system paths are correct in the config.php file. Following the installation wizard should do all this for you. I suspect that you've already discovered this though.
I'm considering using HostPapa. What has your experience been with them? Have you managed to get Moodle up and running yet? Have you fixed the blank screens issue?
Thanks in advance!
BTW, I've found FileZilla to be the most reliable FTP client I've used: https://filezilla-project.org/