I think the thing that you mentioned that is going to have the biggest long-term impact on the community would be the PHP Steem Tools package as it's something that would help other developers bring their ideas to life faster and easier. In that sense, making something for other developers to use has a multiplier effect and thus larger impact (if gaining traction of course).
The WordPress integration might be an interesting idea, especially if it is a step towards a tool that would make implementing SMTs on WordPress websites (or am I vastly missing the way they are going to work?).
As a third option, I would not mind a Steem.Supply Android app and I would surely install it, but I don't think it's something that's really needed. Why put in the effort of making and supporting a whole app when your tool works fine on mobile from the browser. Still, an app with a widget to put on your mobile desktop or lock-screen might be pretty cool, but I doubt it will have huge utility over the website. If you want to have an improvement for mobile, I think you should just improve the responsiveness, that's all.
If you feel like working on Steem.Supply for the hackathon, I think you should consider adding functions it doesn't yet have that people might have asked for in the past. Something I would add might be breaking down the reward for each article into how much the person is getting from each vote and how much exactly is each vote expected to be worth. You could also add monetary values to the Social Insights part.
Good luck on the hackathong and have fun at the event! :)
Thanks for the suggestions, appreciate them all :)
And I appreciate your work and I'm sure so do others :)