Most of the discussions are taking place over here: http://groups.google.com/group/wikipasifika
Regarding a tool to upload many images at once - I'm not aware of one, but am pretty sure that something like this exists.
Post this question on the main list - http://groups.google.com/group/wikieducator and I'm pretty sure one of the technies in the group will have an answer.
Yip if you type in the target url for an external image - to the best of my knowlegdge, it will display. However this potential creates problems around licensing and audit trails linking to images that are not free content.
BTW - welcome on board!