there is no problem at all to install what you have asked for , I have the incoming software installed on one machine and working so good :
* Oracle EE 8.1.7
* Oracle Developer 6i ( Forms and Reports )
* Oracle Designer 6i
* Oracle WebDB
* SQL Server 2000
* Visual Studio 6 EE
On A PIII 700 + 256 M ram + 20 G Hard + Windows 2000 Professional.
I admit that it comes to some how slow when invoking the engine plus 2 or 3 tools simultaniously but it is very cheap nowadays to get a P IV machine with 512 M ram or more plus 40 G Hard at nearly no cost.
IT Manager For Development
Oracle Consultant - OCP