Firmware development is usually a sign that a device's hardware has reached its final form and is unlikely to get any major changes as far as the specs are concerned. Rumors suggest the Galaxy Note 6 will feature a 5.8-inch ‘Slim RGB' AMOLED display, the Snapdragon 823 SoC/a higher clocked Exynos 8890, 6GB of RAM, the same 12-megapixel camera as seen on the S7 lineup but with improved camera software, and a 4,000 mAh battery. We can expect Android N to be powering the software out of the box.
The Galaxy S7 didn't get one, but the Note 6 will come with a USB Type-C port in all likelihood and be water and dust resistant like the Galaxy S7 and S7 edge. One rumor also called for a Galaxy Note 6 Lite with the Snapdragon 820 chipset and 4GB of RAM, but there isn't exactly a high chance of Samsung making a lesser variant of the phablet. What is possible is a curved version, but we haven't seen anything yet to support that particular rumbling from the rumor mill.
Oh, and in case you were wondering, the Galaxy Note 6 will be making its way to Europe.
