Hello @Infinatum,
I left your /var/boot/boot.log
in my post on the other thread because it illuminates the point where your system fails to complete user space. I gather you can skip over the failed step and have a somewhat compromised running system, but with drives you'd like to have mounted still unmounted.
The closest I can come to that is to query systemd
Lbuntu uses systemd to manage Linux on Lubuntu, including orchestrating startup. The log that you posted is a low-resolution rendition of lots of information systemd logs into its journal. If you can get into a shell after skipping over the failed step, then you can query systemd regarding failed services. These may include the drives that failed to mount, as drives are mounted by systemd services.
It just so happens that I have a systemd-based system which is having startup issues. Now while my issues are unrelated to yours, the systemctl commands that I used to probe the issue are not unlike you would use to probe the issue of your drive mount failures.
I'd like to ask systemd about any failed services:
Estella gosgood # systemctl list-units -t service --failed
UNIT LOAD ACTIVE SUB DESCRIPTION
● nfs-idmapd.service loaded failed failed NFSv4 ID-name mapping service
● sntp.service loaded failed failed Set time via SNTP
LOAD = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB = The low-level unit activation state, values depend on unit type.
2 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
Ah - I have two failed services. You, issuing a similar query, may uncover file mounting services that have failed.
I'd like to know details about one of these two failed services. Here's how I ask systemd:
Estella gosgood # systemctl -l status nfs-idmapd.service
● nfs-idmapd.service - NFSv4 ID-name mapping service
Loaded: loaded (/usr/lib64/systemd/system/nfs-idmapd.service; static; vendor preset: disabled)
Active: failed (Result: exit-code) since Thu 2017-03-23 20:42:29 EDT; 34min ago
Process: 280 ExecStart=/usr/sbin/rpc.idmapd $RPCIDMAPDARGS (code=exited, status=1/FAILURE)
Mar 23 20:42:27 Estella systemd[1]: Starting NFSv4 ID-name mapping service...
Mar 23 20:42:29 Estella systemd[1]: nfs-idmapd.service: Control process exited, code=exited status=1
Mar 23 20:42:29 Estella systemd[1]: Failed to start NFSv4 ID-name mapping service.
Mar 23 20:42:29 Estella systemd[1]: nfs-idmapd.service: Unit entered failed state.
Mar 23 20:42:29 Estella systemd[1]: nfs-idmapd.service: Failed with result 'exit-code'.
Now I have a snipped of systemd journal entries centered on my failed nfs-idmapd.service. I have a bunch of hints to pursue.
That's my brief demo in getting systemd to expand detail on what may be going on. There are more examples on this Fedora page:
How to debug Systemd problems
Hope this helps...