Yes, here at OROV we have been playing with unprotected LiFePO cells since January. During our field testing in January in the Sea of Cortez, the Trustfire cells did not tolerate exposure to sea water well. Since occasional leaks are a fact of life in the field, we're trying to find a battery solution that is more robust. LiFePO cells are more rugged than LiCo or LiMnNi, though they have a somewhat lower capacity. They also have a lower voltage, but the ROV runs fine on 9.6 V. The bare 26650 cells are a little shorter than the protected Trustfire cells, so we've been adding a small disc that contains an embedded polyfuse for short-circuit protection of the battery pack.
In short, the cells you list should work, but with a couple of caveats:
1.) They are not protected, so it's up to you to keep them safe from undervoltage, overvoltage, and overcurrent situations. Make sure that your charger will properly work with the lower voltage of LiFePO batteries.
2.) You're probably going to need to add a spacer of some sort to make up the extra room in the battery tubes. The cells you show are flat-topped, and you need to be careful that all the cells make good electrical contact.