I deployed the package and got some issues on the log in:
ERROR: Cookies are blocked due to unexpected output. For help, please see this documentation or try the support forums.
Note that I have cookies allowed, otherwise I could not debug client's sites locally.
I deleted all non-standard folders from the install, inclusive cache, which did not help.
I then removed all Plugins but Toolset and WPML.
This still did not help.
I tried to apply another theme, which also did not help.
I finally found out that this is a Multisite, even thou your Debug information states it is not.
Hence I removed all customizations in the wp-config.php as well and enabled error logging.
I got:
Fatal error: Uncaught Error: Call to a member function get() on boolean in .../plugins/layouts/vendor/toolset/toolset-theme-settings/compatibility-loader/toolset.layouts-themes-factory.class.php on line 31
( ! ) Error: Call to a member function get() on boolean in .../plugins/layouts/vendor/toolset/toolset-theme-settings/compatibility-loader/toolset.layouts-themes-factory.class.php on line 31
I got the same for Views after disabling Layouts.
That might have happened because you used outdated Plugin versions (Types).
I Updated and all was fine.
I finally was able to log in.
But to be honest, it's pointless to proceed now. I changed the initial install so heavily in order to be simply able to log in, that the install is basically not the same anymore.
The strangest is, that the issue still happens, even in this install, even if the page I look at has no View at all included.
All I need to do is activate Views to get circa 3 seconds more load time on the Request URL:hidden link (example)
I have to ask a Developer what I can do here, as I cannot replicate it in a fresh install.
As for the server settings you mention, I will let David Reply here on this, he is a good Server expert.
Although they seem irrelated to this issue. I hope we can find the reason for and update you properly.
Thank you for the patience meanwhile.