A quick search would've helped you quicker...
QUOTE (DmitryKo @ Dec 14 2005, 12:31 AM)

1) can I just put dotnetfx.exe into HFSVPK_SW (it says it supports /Q switch);
I think it will still use the MSI inside the package (which doesn't work during an unattended installation of Windows because it requires Windows Installer 3.0 or higher). You need to make sure install.exe is called. Read the thread I linked to in one of my posts above for more information.
QUOTE (DmitryKo @ Dec 14 2005, 12:31 AM)

2) does NetFX 2.0 runtime replace 1.1 runtime (i.e. can I run 1.1 applets under 2.0);
No. An app may be compatible with 1.1 and 2.0, but the architectures are different.
QUOTE (DmitryKo @ Dec 14 2005, 12:31 AM)

3) what do I do to instal 1.1 hotfixes 867460 and 886903 (they support /Q as well)???
RyanVM has slipstreamed the Service Pack and the hotfix into .NET 1.1 and made a silent/switchless installer from it (to go in HFSVPK). You can download it
here. You'll still need the language pack if you want it in another language.