For a 1998 ZJ, it is completely unnecessary to remove the headlight in order to change its bulb. First, open you hood. Then, all you have to do is unscrew the bulb and its plug from the back of the headlight. Once the bulb and plug have been removed from the back of the headlight, just pull the bulb off of its plug and reverse this process to install a new bulb. The headlight mounting points aren't very strong and are more prone to damage as they age, and if they're damaged--they're a chore to replace. So, if you don't have a good reason to actually remove your headlights--I'd recommend NOT removing them. I damaged one of my 1998 JGC's headlight adjustment screws a few months ago when removing/replacing my headlights and in order to replace this relatively small and simple part I had to remove: all the other front lights, the grill, and the bumper cover--just to access the back/inner-side of the header panel where the damn thing mounts... Needless to say, for a part that cost ~$4--it was quite a hassle...
As far as changing any of the other front bulbs on a 1998 ZJ--meaning the front turn signal and parking light bulbs--yes, you must first completely remove the small corner marker in order to access its (1) bulb and the (2) mounting screws for the turn signal in order to access its (2) bulbs. First, open your hood. Then, to remove the small corner marker, you'll need a regular screwdriver for its (1) upper mounting screw and a very thin, approximately 5" to 6" long Torx #20 (?maybe #25?) screwdriver-type tool to access its (1) lower mounting point. This lower T-20 screw is very difficult to access. Using a flashlight to see, from directly ahead, you must cram your T-20 straight into the basically-too-small space between the bottom of the upper corner marker and the top of the turn signal. Once you've unscrewed both of the upper corner marker's (2) mounting screws, pull it straight forward to remove it. Once the small corner marker has been removed, the (2) mounting screws for the turn signal will be revealed and accessible, (1) of these mounting screws will be a Torx and the other will be a Phillips. Swap bulbs as necessary and then reverse this process accordingly.
You should have no problem replacing the D/S headlight bulb, but you'll need to remove the battery (or at least slide it back a bit) to access and change the P/S headlight bulb. The hardest part of changing the other front bulbs is just cramming that T-20 in-between the corner marker and the turn signal. It will probably be a fairly slow process the first time you do it, but once you've done it, it's fairly quick and easy from then on out.