You should not need liquid wrench on them to get them out and there's nothing not straight forward about replacing them. I'd make sure to hand-thread them in before placing the socket wrench on them, you don't want to strip the threads. I use a 3/8" drive ratchet driver to replace mine, a half-inch ratchet wrench can more easily strip threads in this particular job.
Three good battery recommendations for you '98... The Autolite AP-985 or Champion 3034 are both platinum tipped plugs good for about 100k miles. The iridium-tipped Autolite XP-985 is good for at least 200k miles & what I installed into my TJ 8-9 years ago. All three are great plugs. NGK is ok too, don't go with Bosch which don't run well in our Jeep engines. Avoid gimmick plugs like Pulsar or E-3.
If you also replace your distributor cap & rotor, try to find a set that have brass contacts which last longer than the usual aluminum contacts on cheap distributors & rotors.
Last suggestion if you also replace your ignition wiring... avoid any so-called "performance" ignition wiring that claims "low-resistance". Resistance is actually added on purpose (yes!) to ignition wiring to eliminate static noise & interference to the computer. Low-resistance wiring is actually cheaper to make & just causes problems like static noise in AM and CB radios. The bottom line is the OEM ignition wiring is best.
