The coloring IS off - the leaves should be a bright, grassy-green color. It may be just a case of the tree going through a bit of transplant shock and/or acclimation. No fertilization is required. Japanese maples lean to a slightly acidic soil but will tolerate even a neutral soil pH. What they require is well-drained soil. If planting in clay, you want to plant quite high (top of rootball slightly above grade) in a very wide and shallow planting hole, bringing the excavated soil back in to mound up to the top of the rootball (but not over the top). No amendments in the planting hole but you can use them to topdress or mulch. If you want more detailed info on planting and caring for ANY type of maple, I'd suggest you post on the Maples forum. It is very tree-specific info and addressed by a number of very experienced maple growers :-)) Japanese maples are discussed in considerable detail.

I have some flower seeds. I don't have any Japanese maple trees. Too cold up here! What flowers interest you?

With that much experience, I am surprised your guy suggested October. Especially in some place like CT that can experience sudden and sharp cold spells in winter. Even the ISA recommends dormant season pruning. In addition to other reasons, it makes it far easier to see what and where to prune to get the best aesthetic results when the tree is out of leaf. This link on pruning Japanese maples has some excellent and well-illustrated advice on how to prune to accent/enhance structure or growth habit and how to thin out a congested or too dense canopy. I'm not sure I understand the concept of 'exposing branches' outside of the context of canopy thinning, but perhaps the link will provide sufficient visuals on how a well pruned tree should look.

is it possible to give us a pic of the yard .. instead of just the drawing??? what is your plan for the grass.. kids.. bocci ... that is probably where you should be planting the tree ... the base problem is that you are wanting to plant a 20 to 40 foot tree in a 3.5 foot bed at the fence ... why ...??? and do understand.. tree basically never stop growing .. at some magical height ... they have an established annual growth rate.. and they will grow at that rate until you die ... or it dies ... so.. plan ahead ... get out of the box you are stuck in.. and make a new tree plan ... there are certain tree planting times.. if you cant get it planted in the next couple weeks.. plan on planting in fall .. see section one at the link below ... and then study the rest ... in the meantime.. you can plant the rest of the garden ... its not really imperative to do it all this spring ... no matter what significant other says.. lol .. ken https://sites.google.com/site/tnarboretum/Home/planting-a-tree-or-shrub