That depends on the approver of your application. What I can suggest is to visit the nearest Globe Store, show them all your documents needed to apply for a postpaid plan. To know what are the accepted documents, you can refer at this link Postpaid | Help and Support.
Yes you can still apply for iPhone 6 Plus but not without cash out. In that salary, you can avail a postpaid plan up to Plan 999 if i'm not mistaken. So if you will be applying an iPhone 6 Plus to Plan 999, then there will be a one time cash out or can be payed via major credit card.