1) The about us page is built using the page builder, so you can edit the about page and go to page builder section. Now edit the particualr block and add custom class and then add the custom css using that class, example:
The custom class is "custom" Then the custom css will be
For color: .custom {color:#fff;}
For size: .custom {font-size:14px;}
Refer:
http://prntscr.com/cf7d3s
2) There is no such become a developer template in the wplms, but there is a become a teacher page in the wplms. There is an export code for this, refer:
https://wplms.io/support/knowledge-base/page-builder-export-codes/
3) Go to wp-admin->wplms->miscellaneous->contact page latitude and longitude, change it accordingly and save settings.