Yes, but commercial rights are limited to Sencha Touch. If you want to use Architect with both Sencha Ext JS and Sencha Touch, then you must purchase Sencha Complete or the appropriate Sencha Ext JS license(s). The Sencha Eclipse Plugin for Sencha Ext JS is only available in Sencha Complete.
No. For example, a 1 Developer Pack Sencha Touch bundle can be used by only one unique developer.