IME, some slings will use a hide and others won't. It really depends on the species.
Right now I've got slings who I thought wouldn't burrow, burrowing, and slings that I thought would burrow, not burrowing.
For slings that are prolific webbers, you will probably need to give them something to attach their web to. I really think that all Ts feel more safe when they have a place to hide, be it their burrow, web, or hide.
you can get slabs of cork, and make a depression in the substrate and lay the cork over it...I've had those 3 Tess. and they never seemed to borrow for me....
Also with the avic use some branches or strips of cork on an angle and it will make something IT likes.....When I do aboreal stuff, I tend to pour dirt around the cork base, 1-2 inch deep. Then I pack it tightly and THEN lean the cork to wall. I add some more on the outside of the cork and pack that, so that it is firmly rooted in the soil and doesnt go flopping around when the container is moved. Lost a little red widow that way...
You cannot go wrong With a water dish, so if youve got the room why exclude it? Use a milk cap, or soemthing like that. A friend gave me 100 gatorade caps which I Dishwashed a couple times to be safe....
I don't use hides for the avic or pulchra slings. The pulchra will probably burrow, so make sure he has sufficient substrate, and the avic will probably climb alot, so put in a stick or something and he'll web up the rest. The other two I haven't kept as slings, so I don't know much about them.
Misting should suffice for slings that small. Wouldn't worry about a water dish yet. If these slings are all under an inch, your containers sound a bit big. I find all my slings' containers at Wal-Mart. They've got these powder shakers in their cooking utensil aisle that work really well for a variety of sling. And they're only like $1 or something.
At that size, I wouldn't recommend water dishes. They should get plenty of water from you misting and their food.
You can use some cork bark for a hide or a teeny tiny flower pot (I found some at Michael's that work).
Of course, you'll want to give the A. avicularia room to climb. I recommend glueing a piece of cork bark on the side of the enclosure and it'll build its web off that. Also, it won't need a lot of substrate.
The others may choose to burrow, so I would provide enough substrate to allow them to burrow comfortably if they wish.
Those are roomy for under 1 inch slings! A hide will help you know where to place food offerings, to increase T chances of getting it. Substrate depths: an inch of substrate or less for the Avic. A few inches, or more even, for the other three. Since you will have the space, no reason not to start using water dishes already. Also, for the Avic, I would offer a stick of some type for climbing and web-starting. All my Avics have used the sticks I have offered.
Of course, these are just my opinions. As you have your Ts, watching them and experimenting will give you your best answers, in the end.
Personally, I don't use water dishes for any slings under 1 to 2 inches. I feel safer just misting and not having to worry about a dish, but that's me. As far as substrate goes, my general rule of thumb is one inch per inch of spider and I usually will provide some kind of little hide for them...but again, that's just me.
Your A avic will make its own web retreat. You can put an artificial leaf in with it but that is all you will need. The terresterials, I don't use hides for slings that size. Mostly because I keep them in small containers. If you keep them in a dark corner they will be fine w/o a hide. As for water, just mist the web once in awhile.
I have a 3/4" B. auratum in a vial right now. At first I didn't have a hide and he seemed to walk around all day. So, I cut off a leaf from a silk flower and put the stem into the dirt so the leaf would be raised up a little bit. Now he sits under the leaf most of the day, more relaxed.
When you're slings get a little bigger, try using those black film containers - you know the ones that come with the gray lids? Sometimes they use them as hides and they look pretty cool. You can also use the gray lid as a shallow water dish - it dries out quickly but you don't have to worry about drowning.
I agree with Elizabeth. Your choice of containers sounds large. Most of my slings are in 40 dram vials. It makes it easier for you to keep track of the sling and much easier for the sling to find food. For Ephebopus, I have used small hides, even in vials. They were too nervous otherwise. For most of my other species, as slings their webbing serves as a hide if they decide they want one. When they reach sub-adult size (+/- 2"), I move them to a kritter keeper (they stack well) or a large plastic peanutbutter jar. Then I provide a hide. I have multiples of the species you are getting, all in different stages of development, and I applaude your selection. All of them are great spiders. One note, I have difficulty getting my Avicularias to eat unless I put the prey in their webbing, so I encourage webbing by putting a stick or a small piece of cork in the vial.
I just use the end of the brush to dig a burrow and scatter some spaghnum moss. That does the trick. For arboreal sling, tiny plastic plant and spaghnum moss with enough subs to burrow. Good luck w ur sling.