Wasn't the sharkkaravaratti just great and the chips oh-so-crunchy in the Onasadya you relished? Now, don't waste any of them by letting them go soft or soggy. Tuck them in zip-lock covers, keep them in airtight containers for longer shelf-life.
The array of pickles and the delicious inji curry shouldn't be kept at room temperature for long, for they'd start tasting different. Find glass jars for the pickles as they are acidic, and put them in the fridge.
Did you not finish off the olan? Please do, for the coconut milk has lesser staying power than you'd think. Olan has to be finished within 5-6 hours of making it, or else, it will become throw-out material in no time.
There's enough kalan to probably last 3 days, and that's a good thing. Only, don't heat them. They will go bad real soon if you do. Take a portion of the kalan and keep out in the room temperature before lunch.
How much payasam is left? Quick, chill them and serve after dinner, for they have to be finished the same day.
The rest of the curries—sambar, avial and thoran—would last for a day or two when chilled, but we'll advise you to avoid re-heating and finish them off the same day of cooking.
Lots of leftover veggies? No worries, pack them up neatly in zip lock covers and toss them inside the fridge. All the more better if you freeze them, but either way, not for longer than a couple of days.
