The new A7, A5 and A3 are all are IP68-certified for dust and water resistance. According to Samsung, this means they can survive for 30 minutes underwater at depths of up to 1.5 meters (4.9 feet). Moreover, all three models have NFC, support for Samsung Pay, and fingerprint scanners embedded in their home buttons. This means that the Galaxy A3 (2017) will likely become Samsung's most affordable phone to offer a fingerprint reader.
Speaking of "affordable", according to a flyer revealed in Malaysia, the new Galaxy A7 (model number SM-A720) and Galaxy A5 (model number SM-A520) will be sold at accessible prices: about $424 and $378, respectively. Most probably, the smaller and less powerful Galaxy A3 (model number SM-A320) will cost around $300.
The Galaxy A 2017 user manual mentioned above also suggests that the phones will, unfortunately, run Android 6 Marshmallow at launch, instead of the newer Android 7 Nougat.
For now, we don't have details regarding the US launch of the Galaxy A7 (2017), Galaxy A5 (2017) and Galaxy A3 (2017). But we'll find out more about the handsets on January 5, when Samsung is going to officially announce them.
sources: Samsung Russia (PDF), SoyaCincau via SamMobile