@Imelda, to begin with you only need 2 (or even one) 12v lifepo4 batteries to replace x4 6v batteries. Your 6v batteries were wired to create 12v power.(first in series, then parallel.)
If you don't understand this, and many don't. , I'd highly suggest that you a) go to the rally, and enlist the help of the many who have volunteered above or b) hire a local rv tech to install new battery(ies) and create additional important wiring connections. Imo, there is no real thing that is a "drop in" lifepo4 battery. Especially in your case, wired for 4 x 6 v batteries.
You have done so many great projects on your own. But, this is critical. Loose, or improperly sized, or small wire diameter can cause a fire. Improper settings, or incorrect charging equipment can shorten the life, or disable new batteries, at the most inconvenient time.
We have a lot of people on the forum who have "done their own" with lithium, but they have some extensive study and engineering and/or electrical background, including us.
I've never heard of the second battety you posted. Imo, battleborn is great, and highly overpriced, but great customer service..
Please take some time, and continue to discuss here.