No problems with lounge access on DONE*, they are semi-flexible fares so you can into the Qatar lounges no problem.

So as Mwenenzi says, you just look at the oneworld site to see the options. With your ticket you could visit any (and all) oneworld business lounges in the airport if time allowed (and you're able to get between terminals, and there isn't a domestic/international split). If this is a special occasion and you rarely come to these airports, then you are welcome to lounge hop (e.g. in Doha go to both the Orchard/Gate C lounge, and the biggest one by Gate A/B. Even in Hong Kong you would have access to, multiple Cathay business class lounges along with the Qantas lounge if you wished. NRT will give you the JAL and Cathay lounges too.

Broadly, try to visit the "Home" lounge first, as that will be the best, i.e. where that airport has a locally based airline, so HKG == Cathay, NRT == JAL, DOH == QR (though don't think there is a non-QR operated lounge), then if you get bored try some others to compare. Three hours in DOH can fly by as the lounge has lots of different areas and things to try (e.g. buffet dinner, al-la-carte orders, shower, rest area, light nibbles area), without needing to leave.

Enjoy your trip!