Your VHS tapes will be fine in any Aussie video player. You may be able to deregionalise your dvd player so it will play region 2 and 4 dvds. Try here
DVD Player Hack List
for a simple code which will unlock your dvd region. Many dvd players that you buy here can be hacked. I have a couple of LG players which were dead easy to unlock.
Stereos - no problems there.