Wirelessly posted (Scared of sea bunnies)
Seems a bit redundant to have two separate phones when a smartphone is supposed to do it all. Any reason for this particular setup?
As far as I'm aware of with tmobile you can use a pearl flip without a data plan. If uma usage is big, consider getting the Hotspot @Home (or whatever they are calling it now) plan so calls made over uma are free. As for wifi, unless the rules have changed you should be able to use the native BB browser for web browsing. If that doesn't work, you can easily get an alternate browser like Opera Mini or Bolt 1.5.
In general pages that require log in should work (gmail, facebook) but there are some tha may not (depending on site design). If you don't have a data plan, you'll need to change the browser settings when you get the phone in order to use the native browser.
Sorry can't comment on the other phones as I'm not too familiar with them.