Dealing with business documents on my Windows Phone

I am starting to fill out my apps on my Nokia Lumia 900. The first class of apps I need are the apps to handle all the documents in my job/life — text documents, pdfs, office documents, etc.

* PDFs. Adobe Reader downloads by default the first time you need it, and it seems to be solid, renders well, no obvious problems. I haven’t tried it on huge docs yet but happy so far. Check this one off.
* PDF annotations. There are many apps to view and annotate PDFs on iOS. I am not seeing an obvious choice on WP. I do have the Kindle app and so I guess I could pop them into that as I believe it supports annotations, but that seems convoluted. Is there another choice?
* Signing docs. This is totally lacking as near as I can tell. I can use the web interface of Docusign or Echosign but that is clumsy for an inbound email. Is there a solution?
* Evernote — the evernote app is great, so I have all my text notes. Check this one off too.
* and Boxfiles for Dropbox seems to work well, can fully navigate all my Dropbox content, edit notes. And I can view PPTX, DOCX, etc files. Check.
* As I’ve previously mentioned, I lack a good Markdown editor targetting Dropbox, there are a dozen of these on iOS. Any choices? Does the built-in boxfiles editor support Markdown? I mean of course yes is supports editing Markdown content since that is just regular text with some conventions, but will it render the content into HTML?
* Office Mobile is also on the phone and I can do some things with it — I can create new word docs and edit them, create new xl docs and edit them. I seem to not be able to create new PPTs but can view and edit existing. I can save docs to Skydrive, to the phone. And also to Office365 tho I don’t have an active account for that.

So part way there, some holes to fill. Probably really important to fill these for tablets since I would expect people to do even more document work on tablets.