Thanks for all the great feedback TriMoon and ion. Much appreciated. I may have bitten off more than I can chew here! 
I checked and there are no newlines in the files containing my passwords for the encrypted lvols:
/etc/cryptfs-keys.d/corporate
/etc/cryptfs-keys.d/john
/etc/cryptfs-keys.d/swap
The only reason I went for LUKS on LVM was because I thought there was a big penalty for having FDE and I only needed particular information encrypted (home, swap, company data). Perhaps the hit is not as big as I’m thinking it would be (I have a i7-10875H based laptop) and maybe save myself the headache and go for FDE so I can completely follow TriMoon’s guide?
I’ll need to review… The contents of /etc/mkinitcpio.conf, efi.automount, efi.mount.d/hd.conf, boot.mount, boot.automount is exactly the same as TriMoon’s. What I am not entirely clear about though is what I need to put in /etc/systemd/system/efi.mount.d/hd.conf. I don’t think I can use the example file provided by TriMoon verbatim, but I’m not sure what I need to substitute based on my setup…
Output from lsblk --fs:
nvme0n1
└─nvme0n1p1 LVM2_member LVM2 001 U2ff8Q-BLP0-FHBv-b9Pj-WZOK-Wpr3-3aG5T2
├─vg02-lvol_lxd ext4 1.0 4fea769e-abc4-4fcb-8208-6e7d17c1c950 46.4G 0% /mnt/var/lib/lxd
├─vg02-lvol_downloads ext4 1.0 1efeee99-d440-47ee-8009-76f88430a60f
├─vg02-lvol_install_discs ext4 1.0 044d7519-8473-4b9a-9f0e-43bf913345e1 46.4G 0% /mnt/installDiscs
├─vg02-lvol_libvirt ext4 1.0 0f7ad6ea-4cbc-4c75-90f2-6ace7aba66ea 139.1G 0% /mnt/var/lib/libvirt
└─vg02-lvol_swap crypto_LUKS 1 31906923-c04f-49e0-9dfd-74bcd6435475
nvme1n1
├─nvme1n1p1 vfat FAT32 DBB9-D8DF 281.1M 45% /mnt/boot
└─nvme1n1p2 LVM2_member LVM2 001 tcYhjG-vf2H-Lhxl-SvNb-dGw6-qbqZ-27q4UK
├─vg01-lvol_home ext4 1.0 29f47f99-d263-4076-b2a1-6b990c3a35e6 9.2G 1% /mnt/home
├─vg01-lvol_john crypto_LUKS 1 5ba2e072-c74b-45f4-8e4e-4feae29b2e50
├─vg01-lvol_root ext4 1.0 a319cae0-246f-46a3-a2d7-8c9e2fb6a49a 82.7G 10% /mnt
└─vg01-lvol_corporate crypto_LUKS 1 c6563ef6-38a5-49ab-95cf-6158bb49ffbb
Contents of crypttab.initramfs:
vg02-lvol_swap UUID=31906923-c04f-49e0-9dfd-74bcd6435475 /etc/cryptfs-keys.d/swap
vg01-lvol_john UUID=5ba2e072-c74b-45f4-8e4e-4feae29b2e50 /etc/cryptfs-keys.d/john
vg01-lvol_corporate UUID=c6563ef6-38a5-49ab-95cf-6158bb49ffbb /etc/cryptfs-keys.d/corporate
/dev/disk/by-uuid
...
31906923-c04f-49e0-9dfd-74bcd6435475
5ba2e072-c74b-45f4-8e4e-4feae29b2e50
c6563ef6-38a5-49ab-95cf-6158bb49ffbb
...
/etc/fstab
# /dev/mapper/vg01-lvol_root
UUID=a319cae0-246f-46a3-a2d7-8c9e2fb6a49a / ext4 rw,noatime 0 0
# /dev/mapper/vg01-lvol_home
UUID=29f47f99-d263-4076-b2a1-6b990c3a35e6 /home ext4 rw,noatime 0 0
# /dev/mapper/cryptjohn
UUID=d410f2bb-ed79-4b46-9413-3c3fa9da82bd /home/john ext4 rw,noatime 0 0
# /dev/mapper/vg02-lvol_downloads
UUID=1efeee99-d440-47ee-8009-76f88430a60f /home/john/Downloads ext4 rw,noatime 0 0
# /dev/mapper/crypt_corporate
UUID=1ffd86e7-0d7c-4308-b055-ed41e5a9f979 /corporate ext4 rw,noatime 0 0
# /dev/mapper/vg02-lvol_lxd
UUID=4fea769e-abc4-4fcb-8208-6e7d17c1c950 /var/lib/lxd ext4 rw,noatime 0 0
# /dev/mapper/vg02-lvol_install_discs
UUID=044d7519-8473-4b9a-9f0e-43bf913345e1 /installDiscs ext4 rw,noatime 0 0
# /dev/mapper/vg02-lvol_libvirt
UUID=0f7ad6ea-4cbc-4c75-90f2-6ace7aba66ea /var/lib/libvirt ext4 rw,noatime 0 0
# /dev/nvme1n1p1
UUID=DBB9-D8DF /boot vfat rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro 0 0
# /dev/mapper/crypt_swap
UUID=5474d6ab-a6bb-4a93-9ecb-dbed716ec0bd none swap defaults,pri=-2 0 0
As for the UUIDs in my crypttab.initramfs, I got these from the output of lsblk --fs. I notice though that the UUIDs for these are different to those in my /etc/fstab. Should the UUIDs be the same?