These kinds of installation issues are quite rare.
I'm not sure we have enough information to precisely tell you the problem or how to fix it, but maybe we can start to work it out.
FreeBSD (and thus pfSense) can boot using UEFI since FreeBSD 10.1, however, depending on the BIOS/UEFI in your laptop it might help to enable CSM (Compatibility Support Module) to allow booting in legacy BIOS mode. CSM enabled should generally be the most safe option (my experience).
Regarding AHCI or IDE this is mostly to do with your SATA ports, but may affect USB drives aswell. AHCI mode should be default, IDE being legacy mode for very many years now.
Installation to USB drives is generally a bad idea, since the controllers and NAND chips on USB drives are not really geared for that kind of workload. You should REALLY consider installation to a small SSD or even a Harddrive. At least to work out if the issue is related to the one or more USB drives, that you have attempted to use.