1. It is old and is due to be replaced, although any time table would not be public, nor is it usually released even to support staff much in advance.
2. Two common issues with a T110 II ... 1) system/chipset does NOT support 2003 (not an issue for you, but has caught several by surprise) and 2) good RAID controllers are NOT supported on it (again, probably not an issue if you are going non-RAID for a good reason).
3. I have heard it is, but cannot tell you from first-hand experience.
4. If you are not using a RAID controller, then it should be fine. Why no RAID? If you end up using a RAID controller, then Dell drives should be used. You can get certified Dell drives from suppliers (not usually Newegg) for much less than from Dell directly ... usually a good idea when using on a RAID controller.
5. Not sure ... may simply be the minimum allowable partition size for Windows ... Essentials is 60GB. (BTW ... the 40/80GB options are not possible with these "SBS" OS's - so your only other option is to have the system partition encompass the entire disk space.)
6. Yes, Standard can run 2 virtual instances simultaneously (plus a physical instance to manage them in Hyper-V). Essentials can run only one instance - either physical or virtual - but not both. Foundation has no virtualization rights and must be installed on the hardware.
7. Essentials and Foundation have, together, replaced SBS, and SBS had a restriction (enforced by license) that it must be a Domain Controller and must be the ONLY Domain Controller in the forest. Foundation can be part of a workgroup, but Essentials cannot. Foundation has some other limitations that may make it unsuitable for you. What do you plan to do with this server?
8. I can't say for sure, but it most likely does.