A few updates.
Themes: OK, I spoke too soon about the Themes used on the 360+. I noticed today that when I change the theme to any of the old themes, the 360+ no longer recognizes that there are applications in the "applications" folder and prompts me to add some. When I connect to my laptop and check the directory they are all there but just not recognized.
Calibre library and Wifi: I was able to access my local Calibre using the default browser. However I wasn't able to drill down to actual books. I could see the number of books grouped by tags, authors, etc., but the screen seemed to be stuck in "loading". I will play with it some more this weekend.
CoolReader: I got adventurous and loaded "pkb-cr3-pb-pro-0.0.4-3" this was a great success. I love having choices.
I have confirmed that fbreader180 and CoolReader can be loaded at the same time and still have access to the Applications. It is only switching themes that makes them 'disappear' so I will have to be sure of what is more important to me before I change the look/feel of the 360+. At least I made copies of all the original files before I started playing.