New install on WP 4.7.4, CiviCRM 4.7.18, System Status: Error
I would recommend to get the CiviCRM package from sourceforge, the link is here: 

Also please make sure to follow the installation instruction detailed here for installing CiviCRM in wordpress CMS.

I installed WP 4.7.4 and civi 4.7.18 on local and it got installed smoothly, yes it do gives notifications that you mentioned but that's expected:


Cron Not Running


Configuring cron on your server is necessary for running scheduled jobs such as sending mail and scheduled reminders.


Timestamp Mismatch
Configure Default Mailbox


A default mailbox must be configured for email bounce processing.


Complete Setup


Please enter your organization's name, primary address, and default FROM Email Address (for system-generated emails).