1) "skirmishability" is not a word... I will never play scrabble with you!

2) Actually single 20mm round (or something like that, like 1 penny...) for 15mm is not that bad, provided you do not have hordes to move and frankly the usual African army will have hordes of militia, you will get crazy (on average your militia units will be around 40 strong)... well you can pretend one single mini is a base but then it will look silly. AK-47 is not a skirmish game. so you will have a company with 10-12 figures... sounds silly to me. Ok you will say it is just a representation and you can call the company a platoon or a squad... but then you will end up with a set of abstractions that does not make any sense. Your militia hordes also looks less like hordes. Remember that your standard army in AK-47 is not that small.
Now... what scale have you in mind? If you are going the 15mm way I would say that even in Skirmish sets multiple figure per bases are not bad. I play CoC this way with only the Squad leaders and officers on single bases. Anyway you tend operate by team and squad. Also in 15mm you usually have quite a lot of stuff on the table and frankly single bases slow down. I think that playing with singles will be a great hassle, plus because AK-47 is using bases for everything (some distances, command organization, casualties removal) it will greatly hamper the game play with question like "what group of singles I have to remove?" "who got hit?" "where is my command coherency?".
20mm... well this is probably the best suited to sabot basing.
If you are going 28mm... well I think it is silly, but if you have space and money just make sabot base and no one will care and just drool. I have some sabot bases for my 28mm just in case... I realized that moving more than 15-20 single miniatures is a stupid way to spend my time, also because I do not care about individuals anymore...
3) of course is your game so you decide... but well I think it is nice to warn you of previous bad experiences.