Galaxy J4 is definitely coming. The device has received its Bluetooth certification two weeks ago; moreover, another phone from that series, Galaxy J6, already has its official support page. Seeing how the device’s firmware is now out, it should be out in the next few weeks. Firmware available confirms Android 8.0 Oreo. Info inside it also confirms Pakistan as one of the targeted markets.
Known specs of Galaxy J4 include 8-core Exynos 7570, 2GB of RAM and Bluetooth 4.2 support.