well this is not a photopost support forum so I guess no one responded.
1. You would need to modify showphoto.php and make the alt $ptitle
2. You can rebuild by category instead of all categories otherwise you would need to alter your php.ini file and make timeouts a higher number
There is also an edit you can do to adm-misc.php and add the code in bold where it is shown here
Content visible to verified customers only.
3. Your time thing is simple in the gmtoffset setting in photopost you need to add back in the time from your server to GMT as vbulletin does everything from gmt time back.
So if your server is located in say mountain time you would make a 7 in there not -7 as you want to adjust your server time to GMT to display things right