►▼ Are there any foreign diplomatic outposts in North Korea other than embassies (such as consulates)?
Yes. Russia and China have consulates in the city of Chongjin. France has established a Cooperation and Cultural Action Office in Pyongyang; Italy has an Italian Development Cooperation office in Pyongyang linked to the Italian embassy in Seoul; and the Swiss Development Corporation has a Cooperation Office in Pyongyang overseeing humanitarian aid. (The Swiss ambassador to China is also accredited to the DPRK.)
Additionally, multiple UN agencies responsible for humanitarian and development work are resident in North Korea.
►▼ Do only countries with an embassy in Pyongyang maintain active diplomatic relations with North Korea?
No. North Korea maintains diplomatic relations with countries that do not have official diplomatic representation in Pyongyang. Multiple countries have accredited their ambassadors to South Korea or China to North Korea, although not all such ambassadors are allowed to present their credentials in Pyongyang.