1. Is NFC a universal standard? If iPhones have NFC in a future version will they be able to share files with Androids via NFC?
It should, if it supports the "NFC peer-to-peer" communications mode. This is intended for device to device messaging.
Over that comm link, the NFC Data Exchange Format (NDEF) is used to send simple messages for things like setting up Bluetooth or WiFi connections, transferring contacts, data, photos, etc.
Each message type can be a URI, a MIME type, or a custom designator. E.g. if a web URL is sent, then it's up to the receiving device to ignore it, open a browser, store it as a bookmark, or whatever.
2. Besides sharing files between Samsung devices, are there any other current uses of NFC?
Well, I've never shared a playlist like in that commercial, but many times I've sat next to my son-in-law and we've shared web links, youtube videos, pictures, and apps... it doesn't copy the app, but sends you to the app's page on the PlayStore.
One of the more useful things he and I do with it, is touch to share the Google Navigation to a new restaurant or other place we're all going to in separate cars. That's kind of neat.
There's also those little NFC tags that you can set up to have your Samsung phone do various actions.