Your problem was probably keeping it inside for the winter as maples require a certain period of dormancy for them to survive. In texas the colder it gets during the winter would be better for the tree as they prefer extended periods of 30 or so degree weather. The drainage issue is very important as JMs will get root rot easily if planted too deep or in wet soil. If you don't do it now you will have to dig it up soon and get it above the surface of the clay. It is actually best to practically place the tree on top of the clay (without digging into it more than a few inches) and filling topsoil around it mounding to the side of the root ball. You must also be careful not to allow any soil or mulch to contact the trunk to prevent girdling. I have to be honest things don't look good. But keep your fingers crossed, it might make it.

Many kinds of maples are adapted to heavy soils and are planted in them by the thousands, as along streets for instance. It is the Japanese maple that is unusually touchy about drainage. If this planting site is big enough your best bet would be to excavate the clay soil and replace with lighter soil. If it is a narrow strip and the area becomes quite wet even that may not work, water coming in from the sides. Planting a tree or shrub over loosened soil is not a good idea because as the soils settles after planting the new specimen may sink to a level below the desired depth. Digging organic matter into a heavy soil will not have a lasting effect on the texture of the soil as the organic matter will gradually decompose and disappear. Even when non-decomposing amendments such as sand are used to alter the texture of backfill if the planting area is a small one there will still be the problem of how water moves into and out of the planting area being affected. Small areas of one soil texture surrounded by a much larger area of another are often a setup for problems. A large bed of soil amended with sand or similar material will also pose the problem of what to do when the dug over area rises up like a loaf of bread after the amendments are dug in - unless a soil already has a fairly high sand content a huge amount must be used to alter the texture of the finished bed significantly. If you can't excavate and replace a wide area of soil there or put a layer of more suitable soil over the top then it many just be that you can't safely plant Japanese maples in that particular spot. However, since you are in a fairly mild climate zone possibly it would be acceptable to plant them in suitably large tubs and place these on top of crushed rock or other covering in the same location.

What it boils down to is you will have to make it part of your daily routine to water these every day in summer. More than once a day too if you made the soil very fast draining. And that's if they survive the transplant. If you stick it in your garage in the winter, it won't leaf out in the spring. If you keep it outdoors in the winter, it probably won't take the cold in an exposed container. What you might try doing is burying the container in the ground or in mulch. If you don't mind the headache of doing this for a couple of years or whenever you plan to plant your trees, then go right ahead but you will have a much healthier plant at planting time if you just not buy things until you're ready to plant them. Not only that, if you received a warranty with your plants it will not be valid at time of planting if you wait too long to plant them. You are going to spend far more on time fighting to keep these barely alive for two years that it's worth to buy a j maple 10 times the size of the one you started out with that was freshly field dug from a proper nursery. Not one sitting in a costco. If they still have leaves, I'd return them now. I know this isn't what you want to hear. You want me to tell you they'll do fine and it will be a breeze and they'll grow into magnificent specimens living in a container for 2 years but that isn't reality. You'll thank me later.

"never recommended next to a house". Says who?? Obviously, common sense would dictate that a tree of any size should not be placed smack dab next to a structure, but as long as you allow for growth and spread of the canopy, most JM's can be planted quite close to a house, within reason. Mature spread on a Bloodgood should be ~20-25', so planting no closer than at least half that distance is advised. You can get by with slightly closer placement if you are willing to do some judicious pruning to accommodate (like lifting the canopy to clear a single story roof) but I prefer to allow the tree to do its own thing and would bring it out the recommended distance. There are mature upright Japanese maples planted very close (within 5-6') of houses all over the place here. There is no evidence of damage to either the tree or the structure from this arrangement. Placement "rules" are only guidelines and should be considered with your own preferences and some common sense.