...So do I un solder the clamshell batteries to fit the pismo battery board or not. I'm afraid to do that because I do not want to screw something up so bad.
I recommend choice B) , the "or not"!
The chemicals inside lithium ion cells have a thermal runaway characteristic that is quite deterministic. Heat it up to a certain trigger temperature in any one small spot and it will blow, 100% of the time. Heat can come from an unfortunate combination of battery deterioration causing internal hot spots from laptop current, excessive environmental temerature, and you messing with the pack. The fact that explosions are really, really rare can be credited mostly to three things: first, the combination of the battery board safety features and the internal PTC current interrupter works well; second, the user community is not trying to solder connections to individual cells and overheating them, third, the cells have a very low rate of sudden internal shorting if not abused. While the worst chemical is formed in quantity only in charged cells, there is another that is always present and also releases heat when triggered by temperature. Both runaway at considerably less temperature than a soldering iron, and the entire cell does not have to be at trigger temperature, only a spot need be too hot to initiate the process.
I repeat: the runaway mechanism itself is not a chance thing, it is certain if triggered. The observed rarity of explosions in the world is due to the rarity of all the safety measures in intact battery assemblies failing thus allowing triggering. Please do not try to solder lithium ion batteries or their severed tabs. Because any triggered fire cannot be put out by any practical means, battery remanufacturers have to be absolutely certain the internal cell temperature stays below the trigger point and they usually use controlled stored energy spot welding to do this. If you guess wrong trying to solder a severed short nickel tab there could be an overheat explosion with a flaming venting solvent jet several feet long followed by the entire battery cooking off in a fireball, possibly blinding you and burning down your residence. Even if soldering was perfect, if the cells did not play right with the smart battery controller it could blow while in your laptop. It would be a bummer and not only would you be upset, we would be too!