I've not seen where adding organic matter to soil changes soil pH significantly. When partially digested organic matter is mixed into the soil there could be a temporary "loss" of Nitrogen as the soil bacteria finish digesting that material, but, if that same partially digested organic matter is payed on the soil as a mulch that will not happen.

Now that the leaves are spread throughout the soil (i.e., not concentrated together like in a compost heap) my limited understanding of the decomposition process tells me that fungi will be the main type of organism breaking down your leaves rather than the more rapid bacteria of a compost pile. Valerie has a good point about encouraging the decomposition process w/lactobacteria (see the "One of the best recipe..." posts in this forum.) The worst-case scenario is that you might have a little fun playing alchemist. The best-case is that you'll be adding nutrient availability to your plants and hopefully digesting--vicariously at least--all the leaves in the process. If you have access to used coffeegrounds, you could also dig them in around plants if you're concerned about nitrogen availability. They also might encourage earthworm reproduction and bacterial decomposition of your leaves.

The major reason Ficus benjamina is so ubiquitous is that it's the only commonly available indoor plant that looks like a "tree" in the sense of having a trunk and a canopy with lots of small leaves. So a lot of people grow it because they want that look, although it's not one of the easier house plants, and still needs a relatively high light level for an indoor plant. Doesn't come with colored leaves though. There just isn't a whole lot else to choose from if you want a "tree" like look. Ming aralia, maybe, which indeed looks a little like a Japanese maple and fools some people. Some other good suggestions above. Abutilon does look a lot like a maple but it's a very broad, large leaf, not delicate like Japanese maples, and it needs high light. Bedrooms can be tricky because they generally don't have high light conditions. Maybe evoke the trees or forest via wall decals, and have smaller plants around (ferns?) to evoke the understory? :-)

Nothing unusual; this is the time of the year our summer song-bird migrate. Several small song birds migrate at night, therefore, you may not notice. Ornithologists think they may do this to avoid enemy predators. Starlings and blackbirds are forming large flocks and will move south. In spring and early summer, these same birds vie for nesting and feeding territory and will space apart. After the nestlings have fledged, that behavior subsides and by fall, these same birds flock together with their new offspring. Hopefully, the new birds have developed sufficiently to withstand the rigors of the flight south. I have not seen any juncos yet, but when I do, I will know that winter is coming. The juncos over-winter here and in early spring, they will leave for their northern nesting sites. When the juncos arrive, it signals the end of summer-like weather. At my house, the average temperature has lowered and last week, I turned on my furnace. The autumn forecasters here are predicting that our fall colors will peak a week earlier than last year. This forecast is based on several factors, all weather related throughout the spring and summer. Our colors normally peak around Oct.1 to Oct 10. This year, it may peak by the end of the 3rd week of September.