Foco (Foquismo) is not compatible with anarchism. It explicitly calls for vanguardist cadres, and is based on the Marxist-Leninist revolutions led by Castro and Mao (both of whom are very explicit in both their anti-anarchism and their authoritarianism).
If we are looking back to Guevara as a formulator of Foquismo, he also proves to be a typical authoritarian, even if his methodology of guerilla warfare differed from traditional (to that time) Marxist-Leninist internationalism. Some examples (from his "Guerilla Warfare"):
"It is very important to maintain discipline in the camp, and this should have an educational function." (Chapter 2, Section 3)
"If conditions continue to improve, taxes can be established... Taxes may be collected in money in some cases, or in the form of a part of the harvest..." (Chapter 3, Section 1)
"The important thing, that which must never be neglected in a school of recruits, is indoctrination; this is important because the men arrive without a clear conception as to why they come..." (Chapter 3, Section 9)
"One of the most important features of military organization is disciplinary punishment." (Chapter 3, Section 10)
None of the above quotes would come from an anarchist, at least not one that I would want to associate with. I have chosen not to highlight some parts wherein Guevara writes about the need for flexibility, the primacy of small groups, and other things that anarchists might find appealing, because at root, his theory of peasant-based popular warfare is still an explicitly authoritarian one. This is made even more clear through a reading of his "Bolivian Diaries," where he writes about the practical application of what, in GW is merely theory based on his experience in Cuba. It is also worth noting that Guevara is dead because his theory didn't work out so well in Bolivia.
Some of his conclusions, and some lessons from Foquismo, might be things anarchists can learn from, but we have nothing to gain by adopting the methodology of Marxists wholesale, and I suspect we could learn the same lessons by studying just about any guerilla forces' successes and failures, from the colonial forces in the American Revolution on up through the victory of the Mujahadin over the USSR, to say nothing of the Makhnovschina and the anarchist militias in Spain (neither of which is deserving of uncritical adulation either.)
One final thought, I am personally unconvinced that guerilla warfare, in any of the formualtions I've mentioned here, is the best tactic for anarchists to employ. It may be a necessary tactic at times, but it seems to lend itself to the development of hierarchical authority, which is something we should always be guarding against.
