The Maldives is amazing for relaxing beach holidays and it’s within your range. The tricky thing for most people is that it’s quite expensive for a shorter trip. Of course the Maldives is famous for its water villa resorts, and those water villas start at around US$350 per night. Nearly all of those resorts also have island villas and rooms and those can start at as low as US$100 per night, but you also have to pay for a speedboat or sea-plane transfer from Male Airport to your resort. That can be as low as US$100 per adult for the closer speedboat islands, and up to US$600 per adult for the more remote sea-plane islands. On a shorter stay, that obviously adds to the price. Speaking of that, I run another site all about overwater bungalows and I have links from an article on this site about the cheapest overwater villas in the world. Have a look at that list as it will show you the more affordable options in the Maldives, as well as even cheaper options in Malaysia and elsewhere.
If you’re a bit more on the timid side, you can always use Yelp and TripAdvisor to get good insights on places people have visited. As a disclaimer, some of the ratings may not be accurate on these sites, so make sure you go through and read some of the more recent reviews that people have written. We did this for a few of the places we visited and had no issues.
Oh, did you want a sunny tropical vacation that doesn’t require a passport? Done. Hurricane season is over, flights are cheap, and the water is still warm enough for swimming (and scuba diving). Almost all the tourists come here via cruise ship, which means you’re mostly not competing with them for hotel rooms -- Windward Passage, Emerald Beach, and the Bolongo are all open for business after Hurricanes Irma and Maria last year. On December 16 you can catch Jazz By The Sea down at Coral World Ocean Park, and on December 21 watch the St. Thomas Lighted Boat Parade, where contestants (boats) are judged on lights, originality, and holiday cheer.
During the holidays in Europe, Christmas pop-up markets open in November, bringing intoxicating tastes and aromas (mmm...gingerbread) that brighten even dreary-weather days. On Viking Cruises, for example, the Danube Waltz itinerary enables passengers to experience a variety of markets, which are great places to shop for affordable holiday gifts. Vienna and Budapest both host multiple markets, and each one is different and features different merchandise. Smaller Passau has a more intimate market, and you get to stroll through a charming town to reach it.
Wine aficionados will enjoy sipping Argentina’s well-respected wines, Malbec, a rich red wine, and Torrontes, an aromatic white. Malbec is a perfect match for Argentina’s beef dishes, and Torrontes would make a delightful partner to Milanesa, whether veal or chicken, pounded thin, breaded, and fried. The country’s cuisine demonstrates the influence of Italy; about 3 million Italians migrated there during the late 19th and early 20th centuries. Pizza, pasta, and helado, an ice cream similar to gelato, are as much a part of the cuisine as their asados, barbecued beef grilled on a parillo. Consider a stay at the historic Savoy Hotel, WorldHotels Collection in the artsy Avenue Corrientes area with its elegant neo-baroque lobby, adorned with chandeliers and frescoes.
November brings the annual Vodafone Mexefest Music Festival (Nov. 24-25), a gathering of popular artists in venues throughout Lisbon. The Lisbon & Sintra Film Festival, in its 12th year, is a celebration of cinema with directors, actors, artists, musicians, and writers in town for the event (Nov. 16-25). Billed as the “largest technology conference in the world,” Web Summit began in 2010 as a way to connect industry and the technology community (Nov. 5-8). The year’s new wine and the ripening of chestnuts are celebrated with the Magusto, on Nov. 11, St. Martin’s Day. The holiday spirit becomes apparent at the end of the month, with colorful lights and roasted chestnut vendors along the streets.
If you are looking for beach weather in December then most of your list won’t work, and several of them are only on rivers. Starting from Kolkata you have many good choices that are much closer to you than anywhere in Europe or the Canary Islands, or the Caribbean for that matter. In fact, I’m a bit confused by your list because there are so many different types of places on it, many that aren’t warm or on beaches.
Southeast Asia is easier to deal with, and there are cheap flights connecting in the Middle East and landing in Bangkok, Kuala Lumpur, and Singapore. Each of those is a very interesting city, and there are many smaller places to go in the same region. In Malaysia there is Penang and Melaka. In Thailand there is Chiang Mai and quite a few others in that area. In Laos you can visit Luang Prabang, which sounds like it could be a winner for you. And there is also Siem Reap, which is home to the amazing Angkor Wat temple complex.