you would need to rename the users configuration folder to uninstall the extensions.
for help locating the users configuration folder, see the following tutorial:
if you rename that folder, all extension will be uninstalled. you can then use the extension manager to re install them.
yes, use the same install order. really the install order only has one rule:
dont install eCart last.
the others can be installed in any order.
I prefer the order listed though.