Age to go to 2x's a day feedings?

I'm currently feeding 3xs a day (most days, sometimes I fall asleep early or have to be out all day and she only gets two meals) but I want to cut it down to twice.  I'm wondering at what point I can do that?  The kitten is a little small, 4.5 months and 3.5 lbs.  But she's proportional, she's a bit chubby at this point, honestly.  She's caught up a lot, she was originally very small for her age (only 6.8 ounces at 3 or 4 weeks).  Oh, and she can easily eat 5-6 ounces of food in a setting.  She is a PIG!

Here's a picture of her from a few weeks ago  

Kittens eat a lot because their bodies need all that food for growth. They may look a little chubby but their rest of their bodies will fill out. Some cats are big boned or have super fluffy long fur so sometimes they look fat but really aren't. Somewhere between 6 months to a year, may be more than that for some cats, many kittens start to need less food less frequently. Small frequent meals daily works for most cats. Just two meals a day with 12 hours or so in between each meal is a bit too long IMO.

What are you feeding the kitten? Small meals can be provided daily using a programmable timed feeder. These feeders work for both dry and canned foods. I like the PetSafe 5 compartment feeder. If a feeder is not an option (often pricey as brand new but can sometimes find a used working one on Craigslist or FreeCycle), you can leave a small amount (maybe 1/4 cup or less) of a good grain free dry food out for snacking on.

My cats are adults and one of them eats 4 times a day and the other one eats twice a day with a small bedtime snack. Many other TCS members feed 3 or 4 mini meals daily.

I agree with the above. Your kitten still needs 3-4 feeding per day. I would consider giving her access to kibble or freeze-dried raw (in the dry form) if you do not want to use kibble.

I would say that most cats can tolerate twice daily feeding at around a year or so old; but, honestly most adult cats still do better with 3 daily feeding.

She can't be free fed because my adult cats can't really be free fed dry/dehydrated food.  If I left food out it would have to be urinary tract, which wouldn't be very good for her, either.  Separating her from them isn't a very good option, they get along well and my house is very small.  She also doesn't think dry food is food, since she's never had it.

Timed feeder would simply mean that the adult cats would bully her out of the food and the adult cat on a diet would get too much food.  At this point I have to sit with her when she eats to keep them out of her bowl.  She's been eating 3xs a day for a couple weeks, and is still steadily gaining (even after her spay), so I'm really not concerned she isn't getting enough food right now.  She was a bottle baby, so at one point I was constantly feeding her, it's been a slow and steady increase in the amount she eats and decrease in the frequency of feedings .

She gets a variety of wet foods.  I would say she's probably getting 2/3rds kitten pates (fancy feast, iams, authority) and 1/3rd regular pates (store brand friskies equivalents, friskies, trader joes, authority, etc).  Mostly poultry based, all low carb, some grain/veggie free.  I top her off with whatever is open and in the fridge/leftover in the other cat's bowls after she's eaten her kitten food, which is why she gets non kitten food.

Both of my adult cats are prone to being overweight, so I prefer to feed them 2xs a day to 3xs.  It's not a deal breaker, but it's easier for me and they act less like they're starving.  They fundamentally do not understand the unfairness of the kitten getting a meal and them being left out 

I'll keep her on 3xs a day for now.

I understand having multiple cats with vastly different nutritional needs. I have two kittens, one normal adult cat, one senior cat with CKD, and a senior adult who has a bit of a big girth. I've been losing my mind trying to figure out the best solution.

Thankfully, I don't need to restrict Sara 100% to CKD food. Kitten food isn't great for her but they won't be getting that much longer. I did have to move the kitten food to somewhere my big girl was too lazy to climb to.

I've actually heard of these feeders that can be synced with a cat's microchip. They also include something to be put on their collar (a tag i think) if they are not chipped. It only opens for that particular cat then. It's pretty spendy though. I would LOVE it for my cats, but I'd need a bunch of them.