Re 1, 2 & 3: Sorry, I have not looked at these but suspect installing extra software is required. The N900 is great in many ways, especially in that it's such a blank canvas but sometimes it's a bit too blank!

Re: 4. Office App:
I have to confess I've only done this with word processing docs, not spreadsheets but I suggest you try this...

Open the file using Open Office (Easy Debian*).
Save in native format: Abiword failed to open docx (ms word 2007+) files but OO Writer did fine.
- basic editing was then achieved with abiword.
- suggest complex tasks are done using OO.
When complete, save back to original/nearest ms word format.

To edit, I used Abiword but I wasn't doing anything much. Then save it as a doc (ms word 97 - 2003) file. Abiword had a couple of crashes when asked to 'think'. I presume, from what you've said, this is like gnumeric?

Loading OO can be slow and interaction with it can be fiddly but once running it is very good. in fact, I haven't noticed any problems - at worst, you might experience cpu max-outs for 5 seconds or so. If you have an external kb (? & mouse), it would probably make using OO a bit easier than with the existing kb and stylus; also, the video-out can support 1024 x 768, I think, meaning your laptop would collect a lot of dust!

A trial version of 'documents to go' is available in extras but I haven't used it so I cannot comment. The editing version costs 30USD. It is, however, supposed to be designed for the device whereas OO is a desktop programme.

Hope that helps.

*If you don't have Easy Debian on your phone, the downloader-installer is in extras. The Easy Debian package includes Open Office along with other useful software.