Avira Free Win7 Offline PC

Hello
I need free AV for 2 old Win7 PCs.
I'm thinking about Avira Free.
But:
-1st PC is fully disconnected for web. AV is needed only to occasionally scan USB devices. Is it any Avira offline installer an offline virus database for download?
-2nd PC is online, but "Avira Free Security" not installs.
 Tried manual cleanup as described here: https://support.avira.com/hc/en-us/articles/360003958298-Issues-with-the-Avira-Security-installation
 but it didn't help. I think, it could be caused by firewall (Malwarebytes WFC, but creating rule for installer didn't help, disabling firewall also not help). The best solutions could be also full offline installation.
Regards