Hi, out of the 4, I would recommend the CB100 - it is however the slowest, but that is due to it's self-stabilising 45 degree flybar, which also makes it by far the easiest to fly - but not so easy that you are likely to get bored quickly. Also it doesn't take much to change it into a 4#3B which it is based upon, basically you just swap the head and swashplate.
Starting out with a 4#3B will likely take several weeks of dedicated practice before you are able to hover tail-in, and several months more to be able to do much more than hover - it takes some folk years, and others never get to grips with them.
The 4#6 might be a good one for a beginner providing you are up for a challenge, will probably be a bit easier than a 4#3B to learn with since it is a bit bigger and heavier, being new though there aren't many reports on it. The bigger they are though the harder they fall, so it will likely require more bench time than a CB100/4#3B.
I recommend staying away from the 4G6 until you have some experience. Small CP helis are the hardest of all to learn to fly with. I have a 4G3 and it's great fun outdoors, and very durable for a CP heli due to it's small size and lightweight, but it will break far more easily than any FP, and you don't get to learn to fly so fast when you're heli is on the bench. Also, CP helis are very responsive to stick inputs, and when they move, they move fast. Despite the size, the 4G3/4G6 are not really indoor helis as they need a lot of space. I've been flying for almost 2 years and never do anything more than test hover my 4G3 indoors - which isn't very exciting.