RWFarley:

You can copy the /usr/share/applications/hildon/ooo.desktop file to a new file and change the Exec line to "Exec=debbie oocalc" to get Calc to open.

If you install the basic Gnumeric package, it will install gnumeric-common automatically, and you'll probably get what you need, but you may want to install the gumeric-plugins-extra if it has something extra you need.

As for installing other apps, most apps will work. Games and multimedia apps are the least likely to work.