Quoting Andrew Pam (andrew@sericyb.com.au):
Note that if you do this the drive names can still change when you plug the other two disks back in.
Correction: Merely plugging in discs changes _no_ /dev/sdX device assignments. Changing what's plugged in at boot time often does.
That's why you should use UUIDs and not worry about what names they are assigned.
_Or_ don't change what mass storage devices are plugged in at boot time, and be prepared to occasionally update /etc/fstab if major kernel upgrades change the enumeration order. (Some us consider the cure of UUIDs to be in a spirited competition with the disease.)
With Ubuntu 18.04 it should default to using a swapfile and no swap partition. If you're having trouble with the partitioning, the simplest solution is to tell the installer to use the entire 1TB drive in the default configuration that it recommends rather than doing it manually.
Personally, I always do partitioning and initial mkfs operations using whatever live-CD distribution I most have confidence in (currently Siduction), and then separately let the distro installer use the filesystems and disc layout thus created. But horses for courses.