Welcome! First off, the pot sizes are on the small size, especially for the mint which will quickly take over that size of pot. But, I wouldn't repot until they've gotten over transplant shock.

The basil looks to me like it's just short on water. The pots may be wicking more water out of the dirt than you realize, meaning the plant isn't getting enough. Mint leaves will get larger as the plant matures and is happy. I would keep them in shade until they adjust, then introduce them to sun slowly.

I didn't really understand what type of soil you used. You said you mixed straight fertilizer and compost? Herbs don't need that much fertilizer, and thyme needs a very well draining soil.

Your thyme looks like a standard culinary type. Don't water it until the soil is completely dry.

Thanks a lot! Yes, I mixed dry organic fertilizer and compost. I'm really new to this, so I just thought "The richer the soil, the better, right?" and went ahead of myself. So I'm guessing not every plant likes it rich. Whoops.

How long does it usually for plants to recover from shock? And do you might know of any good recipe for very well draining soil? It turns out plants are a lot pickier than I thought...

And lastly, any tips for raising Thai basics from seed? I didn't know about the concept of bolting, so I bought one that was flowering like crazy :( Thinking of maybe letting it produce seeds to just plant instead...

Again, Thank you so much for your help!

try keep mint wet soil love that and coriander if you ever start that I don't know about eeveryone else but I use 4:1:1 sharp sand and perlite and mine are thriving.

I thought needed loads fertiliser until was told to ignore them water them evry so often in real dry spells or just look at the you will instantly know they need water like today my bay was droupy watered it later that day was straight up.

re- pot them start of the year spring and you are flying they will be well indeed liquid fertiliser once twice are year and thats it

Are you in the southern hemisphere ?

Growing any basil from seeds is simple. But, the soil temperature should be warm enough for them to germinate.
If you are not in hurry, just scatter the seeds , cover them lightly, keep moist ... they will germinate when conditions are right.
I would scatter more seeds than needed. I can always thin them.

If it were me I would plant them in plastic pots. Clay pots dry out 3 times faster. Not real good for down south. You can cut all the flower/slash seed pods off of the Thai basil and maybe leave one or two to seed. It makes a nice medicinal tea.

Okay, now knowing your soil mix, I would encourage you to repot them right away. That amount of a dry fertilizer is very likely to burn the roots of the plant quickly. For my potted herbs, I use a general potting mix that doesn't contain any fertilizer (other than some organics like maybe guano, etc) or water-retention additions. For the arid loving herbs like thyme, oregano, rosemary, I add something like sand or bonsai soil to ensure good drainage, and make sure your pot will drain out the bottom, too! I occasionally use a weak liquid fertilizer when needed (yellowing leaves showing signs of nitrogen deficiency).

When repotting, basil and mint will like a richer soil than thyme. They also like lots more water, and it will be very obvious when they need more--drooping which will perk up almost immediately upon being watered. As stated before, water your thyme only when the soil is dry--every other day may still be too much. If you notice the edges of your thyme leaves browning and dying, it's a sign of root rot from too much moisture. You mentioned tropical--I'm assuming a higher humidity then, so keep an eye on not overwatering.

You can generally tell when they've adapted to transplant when they perk up and start noticeably growing on the basil and mint. They'll kind of stagnate visually above ground while they're expanding root systems. Then, they'll take off. The thyme is a slower grow, so it won't be as noticeable.

Basils are easy to start from seed. Barely cover with dirt and keep moist. Germination is generally very quick. Thai Basil especially likes to go to flower quickly, but it's so pretty too! Continual harvesting of the leaves will actually lead to a much healthier plant. For your mint, harvest as much as you want at a time (you can cut the entire thing to the ground and it will bounce back). Thyme, stick to no more than 1/3 of the plant per harvest.