Unfortunately I don't have any hardware available to test anything that I might want to keep permanently or that I can keep permanently available to test so all testing is carried out using Virtualbox 5.2.12 and the development version of *Ubuntu* 18.10.
1) If I choose to install Xubuntu Core from the main menu, for both 32-bit and 64-bit, I am unable to complete an install due to a crash during the "Installing system" process. After acknowledging the crash I am dropped to a live environment and an *Xfce* desktop rather than a *Xubuntu* desktop. An attempt to install using the desktop shortcut doesn't lead to a successful installation due to a partman error. Sorry but I forgot to record the exact error message.
2) If I first choose to try Xubuntu and then install using the desktop shortcut then for both the 64 and 32-bit ISOs an installation is completed successfully.
If you need me to test anything further then please advise but please bear in mind that at present my hardware resources are very limited.