Just an FYI, that RAM is technically on SuperMicro's compatibility list. Crucial is the consumer arm of Micron. The RAM you've linked to are the same as the Micron DIMM's that SuperMicro has on their HCL. The only difference is the Crucial sticker.

One other things to note is that the USB drives you've chosen are complete overkill and might cause you issues when you plug them in. FreeNAS loads into RAM on startup so read speeds are only an issue when you power up your server... something that you won't be doing very often. The other issue with the SanDisk Extreme's that you should consider is that they're on the bulky side. If you plan to mirror your boot device, you'd have to plug one of the thumb drives into the internal header on the X10SL7-F because it's not possible to plug two of SanDisk's into the rear I/O. I should know, I have an X10SL7-F and two SanDisk Extreme's (and 32GB of that Crucial RAM too).

My advise would be to go with something like the Kingston DataTraveler SE9 G2 as it's no wider than the USB slot itself. They're good quality, have pretty decent performance and two of them fit side by side without issue.

[EDIT 24/07/15] It has come to my attention that some very knowledgeable members over at the FreeNAS forums have sworn off Kingston. Their reasoning is based on Kingston having a reputation for baiting and switching their hardware (including but not limited to the V300 SSD) and the possible high failure rate of Kingston flash drives. As such, I don't recommend using the G2 SE9.

just buy 6 of these on amazon, you can not only wear them, also can use all of them backup death stranding game and save files