There should not be a problem using a TFT with 98SE apart from drivers. Win XP fully supports TFT's via Plug & Play, whereas WIN 98SE probably does not. Therefore you would need to ensure that the TFT you purchase has it's own driver.
A good TFT is the Iiyama ProLite 17" H431S this has a very fast response time of 8msec, and you can download a driver from Iiyama for Win 98SE. If you search you should be able to get one for less than £200. A friend of mine bought one last week from Komplett click here
I would advise that you get a silver one.
As regards Wireless Keyboards......suggest either Microsoft or Logitech.