On both Ubuntu and Ubuntu Gnome, I have working wifi in the installer, but not after. There is no wireless device in the network settings, and I've tried the following with no luck:
WIfi Issues with Macbook Pro Retina Early 2015 (12,2) on Ubuntu 15.04
wifi problem on MacBook pro early 2015 running Ubuntu LTS 16.04
Here are some details:
$ lshw -C Network
*-network
description: Wireless interface
product: BCM43602 802.11ac Wireless LAN SoC
vendor: Broadcom Corporation
physical id: 0
bus info: pci@0000:03:00.0
logical name: wlp3s0
version: 01
serial: f4:5c:89:8e:0f:79
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
configuration: broadcast=yes driver=brcmfmac driverversion=7.35.177.61 firmware=01-ea662a8c latency=0 multicast=yes wireless=IEEE 802.11abgn
resources: irq:63 memory:c1400000-c1407fff memory:c1000000-c13fffff
and
$ lspci -nn | grep 0280
03:00.0 Network controller [0280]: Broadcom Corporation BCM43602 802.11ac Wireless LAN SoC [14e4:43ba] (rev 01)
Edit: It seems Ubuntu is incorrectly treating the adapter as wired on every reboot. Closing and re-opening the lid seems to temporarily fix it for whatever reason.