This has been resolved. The problem ended up being Malware from a rogue plugin. The lesson for anyone else experiencing this issue is outdated, older, or discontinued plugins and/or WordPress installations can result in widespread Malware that replicates itself and causes extreme slowdown on your host’s server resulting in 500 internal server errors.

I appreciate your help on this issue. My host was having problems locating the source, but we got it under control and all back online.