Mint, Oregano and Thyme Selection for Tropical Climate with High

I would like to grow some mint, thyme and oregano. Are there any varieties that will survive the tropical weather with high humidity all year round in Singapore?
I managed to grow sweet basil and lemon in Singapore. I notice that the lemon seem to have growth cycles that are tied to rainy monsoon seasons. I doubt this lemon can flower but the leaves are fragrant.
Daily Temp Range: 28~32C; Humidity: 78%

When it comes to mints, I think many of the varieties that we only rated to zone 9 would do OK in Singapore since they have watermint (Mentha aquatica) in their background. This species grows best when it is hot, wet and humid. The varieties rated to zone 11 are: 'Hillary's Sweet Lemon mint, pink 'Candypops' mint, 'Marilyn's Salad' mint, 'Marshmallow' mint, 'Candied Fruit' mint, 'Citrus Kitchen' mint, 'Cotton Candy' mint, 'Jim's Fruit' mint, 'Fruit Sensations' mint, 'Fruitasia' mint and 'Italian Spice' mint. We also used to carry Jamaican mint (Micromeria viminea) but do not currently have it.
In the oreganos your best bets would be Greek oregano, or better still its 'Kalitera' variety, Hopley's purple oregano and Mexican oregano (this is not an Origanum but Lippia graveolens).
Thyme is more of a problem. We have had no reports of true thymes doing well out of doors all season long in the tropics, but broad-leaved thyme (Coleus amboinicus) is a great substitute for the tropics.
As for the lemon, these trees barely survive the winters in Florida, USA so I see no reason why they should not thrive in your climate. If it was grown from seed, then it may take a long time to reach maturity, that is, flower and fruit. That is the biggest advantage of growing plants from cuttings or grafting a twig of a mature tree onto an immature root stock: the resulting plant will have the maturity stage of the parent plant.