I believe they don't need that much toys to be honest I think 8-10 toys is enough to amuse them and replace any that breaks. If you give them a lot from the start they will get use to it and you will have to buy a lot in short amounts of time.
Pellets also if you start by giving them veggie,fruits and seeds they will become picky eaters. Start by only giving them pellets and veggies as treats they will then believe veggies are special and gobble them up since we all know pellets are bleh. After awhile start giving veggies daily if you want they will then finish everything you give them since its not pellets. Now you can introduce seeds but only as "treats only". This will make the accept different foods more cause who wants to eat pellets. Its not the end of the world if they don't eat veggies daily in the long run.
Cage time is good time. When you first get them don't let them have free access in and out of the cage do not let them out extended periods of time or for the whole day. I know it might seem cruel but they need to learn to play alone inside the cage else they will have nothing to do in the cage and always want to be let out and when they don't get let out they scream, throw tantrums and pluck. They are creatures of habit if they get use to something and it changes bad things happen. Always let them out of the cage by stepping up and not them walking out by themselves. I believe this makes it easier for them to step up and they are more respectful of you since stepping up means fun outside time. It also will make them know this is your place and the cage is theirs.
For them to accepting different people I believe having people formula feed them will make them accept different people. Since regurgitating is the birdy way of saying we are good buddy here's some food. It makes bonding faster and it's good for them in small amounts. Almost all birds love formula so them taking it from a stranger is easier use a needle or spoon. 10ml or less of formula is enough everyday.
Most important I think is that all caiques must know at least one trick it helps you stop them from doing anything you don't want them to do. I suggest roll over. It makes it so they do the trick instead of anything else and helps them focus back on you since they will almost always want the treat. Great way to distract them from unwanted behavior. When training them don't always give them the treat when they do the trick when they are good at it. This avoids them hating you or throwing a tantrum when you don't give them a teat. Try giving them a treat when they do the trick 2 times or 3.
How to teach roll over or stay on your back:
Hold the treat and have them focus you
Say the Command
Palms open and use the back of the hand and gently push them over
When they roll back over or stay on the back give them the treat.
Repeat until you they do it automatically.
They might not listen to command and just know the hand sign which is your palm open and waving mimicking pushing them but your hand is not touching them and above him.
tldr: Everything might seem strict but birds are animals of habit they won't know better unless you introduce it. They are happy with the healthy basics. Do not Spoil them else your life might become hard to deal with and that makes the bird and you unhappy. Birds learn by trying and if they never experience it bad things happen. They can't be use to living the good life else plucking or tantrums will occur down the line when something small changes.
Here's a picture of my baby's all well trained will step up for anyone and all know 3 tricks. I sometimes give them to my friends to take care of or my boyfriend they love him since he's not strict. I'll upload a video of the tricks later on