It appears to make no difference; even with nomodeset, and the intel/nouveau nomodesetting for good measure, the nvidia-modeset executes and hangs at startup:
Aug 18 08:08:34 sager kernel: [ 0.000000] Kernel command line: BOOT_IMAGE=/vmlinuz-4.6.6-040606-generic root=/dev/mapper/ubuntu--vg-root ro acpi_enforce_resources=lax nomodeset i915.modeset=0 nouveau.modeset=0
...
Aug 18 08:08:42 sager kernel: [ 42.831120] nvidia-modeset: WARNING: GPU:0: Lost display notification; continuing.
Aug 18 08:08:45 sager kernel: [ 45.586628] nvidia-modeset: ERROR: GPU:0: Idling display engine timed out: 0x0000957d:0:0:0x00000040
Aug 18 08:09:11 sager kernel: [ 72.177195] NMI watchdog: BUG: soft lockup - CPU#1 stuck for 23s! [Xorg:6165]
Aug 18 08:09:11 sager kernel: [ 72.177197] Modules linked in: pci_stub vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) rfcomm cmac bnep vboxdrv(OE) binfmt_misc mxm_wmi snd_hda_codec_hdmi snd_usb_audio snd_usbmidi_lib btusb nls_iso8859_1 btrtl uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core videodev media intel_rapl x86_pkg_temp_thermal snd_hda_codec_realtek intel_powerclamp snd_hda_codec_generic iwlmvm kvm_intel snd_hda_intel kvm snd_hda_codec mac80211 snd_hda_core irqbypass snd_hwdep snd_pcm nvidia_uvm(POE) snd_seq_midi snd_seq_midi_event snd_rawmidi iwlwifi joydev snd_seq rtsx_pci_ms cfg80211 input_leds snd_seq_device memstick snd_timer serio_raw snd soundcore mei_me shpchp mei hci_uart btbcm btqca btintel bluetooth wmi intel_lpss_acpi intel_lpss acpi_pad mac_hid tpm_crb coretemp parport_pc ppdev lp parport autofs4 btrfs xor raid6_pq algif_skcipher af_alg dm_crypt hid_generic usbhid mmc_block rtsx_pci_sdmmc nvidia_drm(POE) nvidia_modeset(POE) drm_kms_helper syscopyarea crct10dif_pclmul crc32_pclmul ghash_clmulni_intel sysfillrect sysimgblt fb_sys_fops drm aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd rtsx_pci r8169 nvidia(POE) mii psmouse ahci libahci i2c_hid hid pinctrl_sunrisepoint video pinctrl_intel fjes
Aug 18 08:09:11 sager kernel: [ 72.177293] CPU: 1 PID: 6165 Comm: Xorg Tainted: P OE 4.6.6-040606-generic #201608100733
Aug 18 08:09:11 sager kernel: [ 72.177294] Hardware name: Notebook P65_P67RGRERA/P65_P67RGRERA, BIOS 1.05.13RLS1 02/02/2016
Aug 18 08:09:11 sager kernel: [ 72.177295] task: ffff880836478000 ti: ffff88084da28000 task.ti: ffff88084da28000
Aug 18 08:09:11 sager kernel: [ 72.177296] RIP: 0010:[<ffffffffc0da0bb0>] [<ffffffffc0da0bb0>] _nv001875kms+0xd0/0x120 [nvidia_modeset]
Aug 18 08:09:11 sager kernel: [ 72.177305] RSP: 0018:ffff88084da2b700 EFLAGS: 00000293
Aug 18 08:09:11 sager kernel: [ 72.177306] RAX: 00000000000000dc RBX: ffff88084881d008 RCX: 0000000000000000
Aug 18 08:09:11 sager kernel: [ 72.177307] RDX: 0000000000000000 RSI: 0000000001324b84 RDI: 0027059dcf50bf0e
Aug 18 08:09:11 sager kernel: [ 72.177308] RBP: ffff8808364ad000 R08: 0000000000000001 R09: 0000000000000004
Aug 18 08:09:11 sager kernel: [ 72.177308] R10: 0000000000000020 R11: 0000000000000000 R12: 00053a58484cb325
Aug 18 08:09:11 sager kernel: [ 72.177309] R13: 0000000000000001 R14: ffff88084d4a4c08 R15: 0000000000000001
Aug 18 08:09:11 sager kernel: [ 72.177310] FS: 00007fd7e92d2a40(0000) GS:ffff880876440000(0000) knlGS:0000000000000000
Aug 18 08:09:11 sager kernel: [ 72.177311] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Aug 18 08:09:11 sager kernel: [ 72.177311] CR2: 000055d08adc8d30 CR3: 000000084b6c2000 CR4: 00000000003406e0
Aug 18 08:09:11 sager kernel: [ 72.177312] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Aug 18 08:09:11 sager kernel: [ 72.177313] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Aug 18 08:09:11 sager kernel: [ 72.177314] Stack:
Aug 18 08:09:11 sager kernel: [ 72.177314] ffff88084881d008 0000000000000000 ffff88084881c008 00000000c0d93ea5
Aug 18 08:09:11 sager kernel: [ 72.177316] 0000000000000000 0000000000000001 ffff88084881c008 ffff88084881d008
Aug 18 08:09:11 sager kernel: [ 72.177317] ffff88084881c008 0000000000000001 00000000ffffffff ffffffffc0d97713
Aug 18 08:09:11 sager kernel: [ 72.177318] Call Trace:
Aug 18 08:09:11 sager kernel: [ 72.177324] [<ffffffffc0d97713>] ? _nv001769kms+0xa3/0x110 [nvidia_modeset]
Aug 18 08:09:11 sager kernel: [ 72.177332] [<ffffffffc0db2ff8>] ? _nv002008kms+0x1ca8/0x2300 [nvidia_modeset]
Aug 18 08:09:11 sager kernel: [ 72.177337] [<ffffffffc0d7f3f0>] ? nvkms_alloc+0x50/0x60 [nvidia_modeset]
Aug 18 08:09:11 sager kernel: [ 72.177342] [<ffffffffc0d801a0>] ? _nv000310kms+0x60/0x60 [nvidia_modeset]
Aug 18 08:09:11 sager kernel: [ 72.177346] [<ffffffffc0d801ce>] ? _nv000340kms+0x2e/0x40 [nvidia_modeset]
Aug 18 08:09:11 sager kernel: [ 72.177350] [<ffffffffc0d81101>] ? nvKmsIoctl+0x161/0x1e0 [nvidia_modeset]
Aug 18 08:09:11 sager kernel: [ 72.177354] [<ffffffffc0d7fda5>] ? nvkms_ioctl_common+0x45/0x80 [nvidia_modeset]
Aug 18 08:09:11 sager kernel: [ 72.177358] [<ffffffffc0d7fe51>] ? nvkms_ioctl+0x71/0xa0 [nvidia_modeset]
Aug 18 08:09:11 sager kernel: [ 72.177412] [<ffffffffc0083080>] ? nvidia_frontend_compat_ioctl+0x40/0x50 [nvidia]
Aug 18 08:09:11 sager kernel: [ 72.177453] [<ffffffffc008309e>] ? nvidia_frontend_unlocked_ioctl+0xe/0x10 [nvidia]
Aug 18 08:09:11 sager kernel: [ 72.177455] [<ffffffff81239c03>] ? do_vfs_ioctl+0xa3/0x5d0
Aug 18 08:09:11 sager kernel: [ 72.177456] [<ffffffff81228061>] ? __sb_end_write+0x21/0x30
Aug 18 08:09:11 sager kernel: [ 72.177458] [<ffffffff812256bc>] ? vfs_write+0x14c/0x190
Aug 18 08:09:11 sager kernel: [ 72.177459] [<ffffffff8123a1a9>] ? SyS_ioctl+0x79/0x90
Aug 18 08:09:11 sager kernel: [ 72.177460] [<ffffffff8184cf36>] ? entry_SYSCALL_64_fastpath+0x1e/0xa8
Aug 18 08:09:11 sager kernel: [ 72.177461] Code: 44 21 f8 41 39 c5 74 45 e8 ee e9 fd ff 44 8b 9b 80 04 00 00 45 85 db 75 e4 49 39 c4 73 df 48 8b 4c 24 08 49 8b 44 ce 60 8b 40 04 <41> 39 86 b4 00 00 00 75 c9 48 8b 7c 24 10 48 c7 c2 28 79 df c0
UPDATE: Going to add nvidia.modeset=0, which I notice I didn’t add, and try again.