Hi Cal

I assume that as you're asking about lounge service you're flying C class...? Lounges outside Qatar will normally operate IAW local policy, so LHR, SIN etc will not change (they're 3rd party lounges anyway). Lounges in Muslim countries, especially GCC, may well be subject to restrictions. The Premium Terminal in Doha will not be serving alcohol for the duration of Ramadan.

I've never traveled C class on a regional flight but on long haul the service is 'adjusted' for Ramadan. For instance, rather than bringing a Champagne bottle to your seat & filling the glass in front of you the glass will be filled in the galley (effectively out of sight) & brought to you. Still plenty of alcohol for everyone though. I'd guess that the regional flight service depends on the destination.