Alright, I'll be the one to say it: all of these have been available as PhoneGap plugins for a long, long time.
This is the problem with building a paid-for subscription service like this- no-one is going to help you. By the nature of being open source, PhoneGap has a ton of developers willing to donate their time to extend the existing functionality in any which way you could want.
Unfortunately PhoneGap sucked to get started on the last time I tried it. Trigger, I had an app running about 2 minutes after getting to their website. PhoneGaps cool as it's opensource, Trigger is cool as it just works, has support and great docs.
I'd suggest you give it a try. p.s. I do not work for trigger.
This just keeps getting better and better. I know of several non-coders whose 'learning to code' project was building a working iPhone app, all because of Trigger.io! Badass.
This is the problem with building a paid-for subscription service like this- no-one is going to help you. By the nature of being open source, PhoneGap has a ton of developers willing to donate their time to extend the existing functionality in any which way you could want.