Is there any way to stream audio and video files from Windows laptop to iPhone 6 plus at anytime with my own wifi hotspot?
Download FileBrowser App from Apple Store you can get the lite version for free and if you are Jailbroken you can get the full version from Appcake and it will solve your problem

Once you have installed the App connect your PC and phone on the same network. App will scan available devices on the network to connect select your PC and then you can browse the files select the one you want to stream and thats it