Ultralight and long term dont go well together...
I wrote you guys a mail, but besides that:
Dont take anything made of plastic. I read that you'll be biking and canoeing parts of the tour. When i cycled through africa i had to bushcraft/improvise lots of stuff on the bike that broke, because it was plastic. The bottleholder, speedometer holder, buckles...
Seriously, dont take plastic cuttlery with you. I also carry a leatherman, the surge. I had it with me hiking and never used it, while a constantly used it while on the bike. So take it at least for the bike part. Also Park Tool and Topeak make small, lightweight biketools.
For the sleeping bags: -17° ? I know you have some rough weather, but i'd rather take 2 smaller sleeping bags with me. One synthetic (outer shell) and another downbag (inner shell) That way you can modulate the insulation, use a lighter one in summer and both in winter/colder nights. They also dry a lot faster, because they are half the size and the insulations of the outer one works when wet.
Wet... Invest in good waterproof bags. Raincover for backpacks wont do it. Use Drybags, my personal favourite is Ortlieb. Certainly not Light, but durable. I used one pair for all my trips, and they are still good. Just keep the downbags dry, the rest is not as important.
Eating: I carry a selfbuild alcoholstove. Before that i used a MSR Multifuel, worked perfectly, but weighted 700 gramms more. The alcohol is a bit more expensive then gasoline, but you also get it everywere and the stove itself is cheaper and weights only 15gr. and if it breaks, you just need 2 cans and your leatherman ;) I use a pennystove. Just google it and you'll find descriptions on how to build one.
Sleeping: Foammats are good, no problem with holes... I carry inflatable mats and have to fix about 1 hole every 3 months of use.
Biketires: Schwalbe Marathon Plus. But guess you heard that name already. I used one pair from Germany to Kenia and the second from Kenia to Capetown. Only 7 flat tires. I met people doing 15000km with one pair. Well worth the investment.
Towel: Just use a Buff.
Clothing: For long use I'd take Merinowool. Also heavier then synthetics it's much more comfortable (personal reference), it wont smell (you can literally wear it for a month without washing) and the insulation works better. Still, just personal reference and most people agree on disagreeing about wool vs synthetics.
Barefoot walking i did one month in India with a 35l 12-15kg backpack. Barefoot as in no shoes at all, just for the heck of it because some indians are doing it as well. The feet get used to it, no problem with the knees or anything. BUT you will get cuts and bruises and since india is supremely dirty they got infected and whatnot. I really dont recommend walking without shoes. Just think of camelspiders/scorpions in your middle-eastern part ;) I also had a pair of Nike Free once, but they didnt survive long. But that seems to be the case in every ultralight trailshoe. They are designed to do 500-1000km and then you need new ones.
Bagpack: Golite packs seem to survive rather well, considering Andrew Skruka carries one. But no personal experience.
Route: Look at my email :)