Joomla version: 3.6.5
jms_v1.3.63_full
partial_usersharing_v1.2.04
php 7 version

Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; plgUserPartialUserSharing has a deprecated constructor in /home/testing/stores/plugins/user/partialusersharing/partialusersharing.php on line 44

Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; Site has a deprecated constructor in /home/testing/stores/administrator/components/com_multisites/classes/site.php on line 35

Warning: Declaration of MultisitesElement::render(&$xmlElement, $value, $control_name = 'params') should be compatible with JFormField::render($layoutId, $data = Array) in /home/testing/stores/administrator/components/com_multisites/elements/compat16.php on line 27

Deprecated: Non-static method JDatabase::getAdapter() should not be called statically in /home/testing/stores/administrator/components/com_multisites/libraries/joomla/database/j2windb.php on line 58

Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; Jms2WinDBTables has a deprecated constructor in /home/testing/stores/administrator/components/com_multisites/classes/dbtables.php on line 29

Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; Jms2WinTreeSearch has a deprecated constructor in /home/testing/stores/administrator/components/com_multisites/classes/treesearch.php on line 27

Fatal error: Maximum execution time of 30 seconds exceeded in /home/testing/stores/multisites/cs899/config_multisites.php on line 1

Deprecated message does NOT means not working.
This is a message reported by PHP 7.
We kept old syntax to remain compatible with old environment.

Concerning the Fatal error, it reports a maximum execution time.
I don't know what may cause this long time execution.
Did you tried increase the time.
Check the content of the file
/home/testing/stores/multisites/cs899/config_multisites.php on line 1

I suspect that you have a hack or something strange in line 1