Yes, Symbian OS based devices (except those released by DoCoMo in Japan) are open phones and applications can be installed from an open market (not controlled by the manufacturer, like in iPhone's case). So yes, a divx player is available, the real player is built-in, at least in the S60 devices.
If the phones you mention are Symbian OS based then yes, you might be able to find the above requested apps, just do a bit of search for "divx player UIQ"
