Your conclusion that the first motor is the most powerful is correct, given those figures. Note that its peak current is 5A, so you'll need quite a substantial motor driver and battery; either a 4-cell LiIon pack with a suitable rating or a car battery. You may find a car battery a useful weight for holding the whole system on the ground!
Putting a DC voltage on a brush motor with polarity opposite what the motor would generate itself is called "plugging". It will cause the motor to consume current in excess of its stall current (up to 2x), but it will stop the motor faster than would dynamic braking. Indeed, the torque trying to stop the motor may be twice the motor's starting torque. All of the electricity fed into a motor under such circumstances will be turned into heat (which could cause overheating if one isn't careful); further, the extreme torque may damage whatever the motor is connected to. Nonetheless, if one really needs to stop a system instantly, plugging is a way to do it.
Things are a bit different with AC, however. If one drives a motor with an AC signal which is connected to a battery in "forward" polarity some fraction of the time and in "reverse" polarity the remainder of the time, and if the frequency is high enough the motor current doesn't have time to change much during each cycle (due to the motor's inductance), one may by varying the "forward" duty cycle control the motor speed to be anywhere from forward full to reverse full. Three really nice things about this control approach:
-1- Its behavior is relatively linear; for example, driving the motor 75% forward 25% reverse will make its no-load speed be about 50% of its forward no-load speed.
-2- If one is willing to drive the motor with less than its maximum stall current for a given supply voltage, the supply current will be reduced proportional to the square of the current one does use. For example, if one is willing to settle for half the stall current, supply current while starting will be reduced by 75%. If one only needs a third of maximum stall current, supply current can be reduced by almost 90%.
-3- Provided that one tries to drive the motor at some speed in its direction of motion, it will automatically perform regenerative braking (maximum regeneration power can be achieved by driving the motor at a speed half its current speed; maximum efficiency can be achieved by slowing down the motor as gradually as is tolerable).
The amount of power a motor will waste as resistive heat is proportional to the square of the torque it's generating, which is in turn proportional to the difference between the motor's present speed and its "requested" speed. Although trying to switch motor polarity many thousands of times per second may incur some switching losses, trying to keep the requested speed close to the actual speed can help achieve some very good efficiency.
Best Answer
Induction motors 101.
In an induction motor, the supplied voltage creates a rotating magnetic field around the rotor. If you consider a two-pole motor running on a 60 Hz system, the rotating field moves at 60 Hz * 60 sec/min = 3600 RPM.
In this case, 3600 RPM would be called the "synchronous speed." Meaning that if the rotor actually was spinning at 3600 RPM, then the rotor and rotating field are in-sync.
But in normal motoring operation, the rotor spins a bit slower than 3600 RPM. This speed difference, called "slip" gives rise to a current in the rotor which then generates torque. The larger the slip, the more torque the motor will produce, to a point. So, basically, as you apply a load to an induction motor, it slows down a bit, and the torque increases, until the motor and load balance each other out (or maybe if the load is too much, the motor will stall).
The way you put an induction motor into regeneration is to simply increase the mechanical speed of rotation higher than synchronous speed. In our example, this means you need to make the rotor spin faster than 3600 RPM. You could do this, for example, by connecting another motor (maybe a gas motor) to your electric motor, then over-drive the electric motor with the gas motor. Now you have an induction generator rather than an induction motor. You will be supplying power to the electrical grid instead of using the power from the grid. You don't need to do anything else. It just happens.
Now lets consider a motor running from a variable frequency drive (VFD). The VFD can control the frequency of the voltage applied to the motor, which means it can control the motor speed. If the motor is turning a giant heavy turntable, for example, and the VFD needs to slow it down quickly, then the VFD will apply a frequency lower than the actual rotation of the motor. Because the electrical frequency is lower than the actual rotor frequency, the motor will be in regen. This will cause mechanical energy in the turntable to be converted into electrical energy. The VFD may even have an over-voltage failure when this happens, unless it has some way to dump the extra energy (for example into a load resistor). Because of the way they are designed, VFD's usually cannot put energy back into the grid.
There is a lot of other stuff that could be written about this topic, but these are the basics. If the rotor is spinning slower than the electrical frequency, then the motor is operating in the usual fashion, as a motor. But if an external force speeds up the rotor faster than the electrical frequency, then the motor will naturally transition into regen as it converts mechanical energy into electrical energy.