Can't help you on the fatwood but I would warn you about the powdered magnesium in a film can trick. The film can must be completely air tight and oxygen depleted before you seal it or the magnesium will be oxidized before you try to light it (oxidization is what burning does) and thus be useless. The oxidization will be slow and low temp unless you light it but it will be inevetable if you powder it ahead of time.

RE maya / fat wood, you might consider collecting some birch bark. White birch has an inner bark (below the flaky papery bark but not the wood) that can be up to 3/8" thick. this is quite resinous and when started with the papery bark provides both tinder and kindling. Also it is free and widely available and can probably be collected wherever you need it and it does light even when wet. Catching a spark with the papery outer bark is rather easy if you fray it enough and it is dry.