Definition of terms
While there was an accepted definition of the term "assault rifle" (before the gun grabbers started calling everthing with a pistol grip and detachable mag an "assault weapon"), there was no specific definition of the term "battle rifle". But there was a generally accepted definition. Here they are.
Assault rifle: Selective fire military style rifle firing an intermediate size cartridge.
These two features (selective fire and intermediate size round) are the key factors in whether or not a particular rifle fits the definition.
Battle rifle: A military style rifle used (or intended for use) in combat firing a "full power" (or full sized) round. The key factor here is military use (actual or intended), and the full power cartridge. Note that it makes no mention of action type. Bolt actions (even muzzleloaders) were the "battle rifles" of their day. Later designs were selective fire, but they retained the full power cartridge.
Full power rounds are judged by the standards of the early 20th century. Rounds that match the ballistic envelope used by the cartridges of major powers during WWI/WWII in their main service rifles. Some of the rounds during the wars are lighter and less powerful than others, but they are still considered as "full size" or full power rounds.
This includes ALL recognised standards, as well as some of the lesser known ones. .30-06, .308, 7.62x54R, .303 British, 8mm Mauser, 7.7mm Jap, 7.5mm Swiss, are all ballistically close to each other. Lighter cartridges include the 6.5mm Jap, 6.5mm Carcano, 6.5mm Swede, and others. There are quite a few military rounds that will fall into this broad range, even though not used in major wars (ex. 7.65mm Argentine), they should still qualify.
"Intermediate" cartidges were developed during WWII, with the intent of creating a lighter handier rifle/ammo combination, (which used less valuable resources) and still had sufficient power for combat. More powerful than standard pistol rounds, but not as large and powerful as full size rifle rounds. The German 7.92x33mm was the first fielded. Later the Soviet 7.62x39mm was introduced, and became the Communist standard worldwide.
The US took the concept and went a slightly different route. The .30 Carbine (an oversized pistol round) was developed and fielded as a replacement rifle for troops who's main function was not combat, as it was recognised that they needed something with more range and more easily used than a pistol. The (relatively) light carbines found favor with the combat troops, because of their size/weight, and their firepower (15rnds vs 8, standard) Later, when the US decided the full size round was no longer needed for riflemen, we went a different route, going to a small bore high speed round, the 5.56mm (.223). This was a departure from the regular intermediate round formula, as previous designs had retained the full power round's bore size. Although we went about it a different way, the overall effect was approximately the same. A round with a useable combat range of between 300-400 meters.
Now, we are talking about civilian legal (semi auto) rifles, so technically the term assault rifle does not apply. However, thanks to the gun grabbers muddying the popular definition, assault rifle and assault weapon is used by many for any rifle that looks like an actual assault rifle. Call it what you want, but if you are going to get into guns, learn the real difference.
Of the guns on your list, only the AR10 and the FAL would be proper battle rifles. AR15, SKS, and AK are not. Call them carbines, or semiautomatic assault rifles (an anti gunner's term), but they are not to be considered battle rifles, due to the round that they shoot.
Of those listed, the best bargin is the SKS, in terms of dollars, as long as the round meets your requirements for range and power. If you need an actual battle rifle round, trhe FAL is cheaper than the AR 10.
Hope this helps.
What is your enemy carring? 
Bottom line, if I'm in a warzone, screw the M-16.
