Your server has disabled a core PHP function exec via the disable_functions directive in php.ini. This may cause unexpected problems in XenForo.
Your server has disabled a core PHP function proc_open via the disable_functions directive in php.ini. This may cause unexpected problems in XenForo.
Your server has disabled a core PHP function popen via the disable_functions directive in php.ini. This may cause unexpected problems in XenForo.
No, those are unrelated to this issue.
exec is required for XFMG and FFmpeg integration - if you don't have XFMG then it's not required.
proc_open and popen are required for email delivery when using the built in PHP option - they are not required if using SMTP.
I suspect it's an artefact of the import, possibly due to unexpected/corrupt data in the SMF2 forum.
Submitting a ticket with ACP and phpmyAdmin/cPanel/server access will be required to investigate further,
< / img > is not proper HTML. The img tag is like the BR tag, self-closing. That's a problem. Also the England tag has a proper closing < /a > tag, the other does not.
I'm happy that resolved it. I've run into this issue (as well as = instead of == in code!) in my career more times that I can recall. Very common mistake we all make.