I find the lack of at least one legacy USB port extremely worrying. Will the following work with a USB to Firewire/USB-C dongle?
* boot from USB (bootable CarbonCopyCloner backup)
* Yubikey (government issued, so I can't easily get an updated key)
* Kensington R800 presenter (supposedly, it's "just a USB keyboard", but I've had it not work via Bluetooth dongle or with the USB to Lightning dongle for the iPad, even though regular USB keyboards work)
USB C is just the form factor. USB 3.1 Gen 2 is commonly supported by USB C ports. USB 3.1 Gen 2 is backwards compatible with USB 3.0/3.1 and 2.0 but not USB 1.0/1.1. You may need an active adapter or hub from 2.0 to 1.1 instead of just a passive cable.
* boot from USB (bootable CarbonCopyCloner backup)
* Yubikey (government issued, so I can't easily get an updated key)
* Kensington R800 presenter (supposedly, it's "just a USB keyboard", but I've had it not work via Bluetooth dongle or with the USB to Lightning dongle for the iPad, even though regular USB keyboards work)