Choosing the right LiPo Battery
If the motors run continuously, with no changing load, and actually draw the rated power, and if the batteries actually retain and deliver as much power as they specify, and ignoring other effects and losses, then:

8 motors * 6A/hr = 48A/h

6 motors * 5A/hr = 30A/h

48 + 30 = 78A/h

Adding 15% for losses and safety margin,

(78 * .15) + 78 = 89.7A/h

If you used a 60A/h battery array on an 89.7A/h load, you could expect 60 / 89.7 = 0.6689 hours of operation.

If the motors were only "on" half of the time, then 2 / 89.7 = 44.85A/h, 60 / 44.85 = 1.34 hours.

Paralleling and charging multiple LiPo packs can be problematic. The better packs include a second connector for charging, which allows each cell to be individually charged. Any bank of LiPo's must be charged per-cell for safety. Some sort of power distribution, regulation, monitoring, and per-cell charging system likely needs engineered. LiPo's are very touchy about going over and under cell voltages and working in cold temperatures also.