In this set of photos, the first maple with red leaves does not look grafted. This is possible, in the USA the JMs 'Bloodgood" and "Emporer I" are available from tissue culture (which like a cutting, would be true to type and have no graft scar).
Second photo I can not tell, need a better photo of its trunk.
Third and fourth tree do not look grafted.
Fifth photo I believe is the same tree as the first.
I think with all of them, if they were mine, For 2017 the only thing I would do is repot them to growing trays or boxes. The trays or boxes should hold the same amount or more potting media than the pots they are in. I would recommend the new growing tray should be less than 5 inches deep, 4 or 3 inches would be ideal. I don't remember where you live, so I can not give you a date, but in spring, when new buds are just about to break open and leaves are about to pop out is a good time to repot. At the time of repotting you can prune downward roots, prune off roots that are too thick, you can create a nice flat radial root system. Don't prune the top of the plant. Since you are repotting as the new buds are about to sprout, the tree will open only the amount of buds it can support. If you prune off more of the top than needed to "balance" the roots and leaves, you will not get the best root growth. To get the vigorous roots you need, you want maximum amount of foliage. So keep the top, it will help the tree grow the largest, most vigorous root system it can. Let it recover all of 2017 with no other work, other than watering & fertilizing. Use a media that is well draining but has a fair amount of organics. At this stage I like a blend of perlite and what every your favorite nursery style mix. I use roughly 50% perlite, the rest being Promix, or other good quality potting media. NOTE - I do this with maples, I do not use this media with pines. Maples like a rich moist soil. This will work well. Perlite is very lite weight. Makes moving around these big flats an easier task.
I use Anderson Flats. They are 15 x 15 x 5 inches deep, and have mesh bottoms. They are heavy black plastic and will survive in full sun for 10 or more years before becoming brittle. They retail for about $10 at a number of Bonsai Supplies sellers, or can be purchased directly from Anderson if you do a 50 piece minimum order. They hold about 4 or 5 gallons of media, so are good as grow out trays for most nursery stock in 1 to 5 gallon nursery pots. You can build your own boxes, use similar dimensions. Use wire mesh to cover gaps left for good drainage. Nothing special about anderson flats except they are easy and made to a convenient dimensions for my purposes.
I would let all the trees grow with no work for all of 2017, maybe even 2018. Don't start chopping, air layering or "training" until you have vigorous growth, they need to look full and bushy. If at the end of 2017 they don't have considerably more foliage than they have now, you need to investigate your horticulture, and make improvements and see if you can get them bushy by the end of 2018. Then they will respond well to what ever you end up doing. And gives you time to learn a few things before making choices that you can not easily undo.
I like the red leafed maple a lot. The rest can work, but the red leaf one I can see it becoming bonsai.
