If you know some people with different reels, I'd see about getting your mom to try a few out. Won't really matter the brand of size right then but weather or not she can pick up on casting easily enough. I can't stand those closed face spin cast reels but they just might be the easiest to learn to cast on. Then the spinning reel and there are more of them out there than anything. Highly unlikely anyone has tried them all. Not difficult to cast at all but your not gonna pick any new to her reel and have her doing well from the git go.
That Zebco 33 is a spin cast. Friend of mine in Montana years ago only fished with those spin cast reels, he loved them. I didn't have much luck with them though. Hard to recall but seems to me that to heavy mono line on them could cause some ugly mess's. Almost like level winds but the Zebco has that cover on it. But it is worth a try to see how your mom get's along with it.
Spinning reels seem to be sized according to their mod number. I think I read where a smaller number meant a smaller reel. But I never realized that and have always simply looked for a size I though I'd like to use. These days mostly ultra light reels but have a few older reels two Mitchell's you'll only find used anymore and an old Daiwa J 25 that seems to me is a bit bigger than the Mitchell's. Draw back on the Daiwa is it is a bit heavier than the Mitchell's and probably the newer reels about the same size.
For me there is a flaw in spinning reels and that is using monofilament line. Some of the line has a lot of memory, in that try to cast it and it comes loose off the spool and causes a mess, not always but enough to aggravate me! But I still use monofilament on all my spinning reels. My son use's braid on his and I don't know that that ever happens to him. I have finally switched over to braid on my level wind reels and the memory problem with monofilament has completely disappeared and seems they cast easier. That memory problem generally shows itself with heavier test line but can come around in lighter line also. I think what you might look for is a line claimed to being soft, might have less memory. And if all you are fishing for is eater's, stay about 10 to 15 pound test main line.
I'd definitely stay away from level wind casting reels. They can be terrible to learn to cast and you get your first bird nest with one and you will never forget it, probably turn you off right there! Spin cast as the Zebco 33 mentioned by a lot of other guy or spinning would be the way to go. BTW, what do you use? I'll guess spinning as it seems to be the most popular type out there. Take your mom out and let her try it in the yard. Who knows you might have just what she needs.
If I were going to look for a new spinning reel myself I'd look hard at Ocuma, I've had real good luck with their ultra lights. Then inexpensive I'd look at Shakespere and Pflueger president. I've had a couple Plueger's and really liked them. And seems to me the cost was down on all the three I mentioned here. I doubt you mom will use any of them enough to wear one out anytime soon. Shamino makes very vice spinning reels and Garcia has a good name and I would check them out.
There's a number of different spincast reels out there and generally they seem to be inexpensive. I think the best known is the Zebco and seems that Zebco 33 has been around a long long time. I think that is important as longevity seems to reflect a certain level of quality, people keep buying them. I think I had a little Shakespere at one time but gave it to my son before I ever used it. Actually I am to negative about spin casting and know it but think you probably should look at them. I'm big on round level wind casting and am sure you should avoid them for getting going.
Then there is the rod. For myself only I don't thing there is a rod made worth $100! I keep the cost of rods down below $50 and that's a lot for me. Lot of fairly nice rods out there fairly inexpensive. Lot of time's the way to go might be getting a reel and rod already set up. Look just in front of the handle on the rod and you should see what line weight and lure weight is suggested with the rod and it's action and length. I like rods 6.5 to 7 foot. have a couple 8 footer's and just not crazy about them. For line, no matter what it say's you could put on any line you like and it will work in some matter. better to look at the size of fish your targeting. I'm not so sure I'd call any fish, cat fish, over 8 to 10 pounds an eater. Seems people claim the food quality goes down somewhere around ten pounds. That in mind you might look for a line rating of 8-17 pounds. any fish that will break that 17 pound line you probably wouldn't want to eat in the first place. I like medium action rods with fairly fast tips. You'll notice that a rod like that usually has a lure rating up to something like 3/4 oz. With that I have no problem with 2 oz sinker's but I have managed to break 12# mono casting if I forgot to release the spool on my reel. In time you learn to pay attention to things like that but learning can be a slow process! Anyway just the reel is not enough, you need to think of the rod also. I like reasonably stiff rods with med fast tip's, that is a rod with not to flimsy a tip if you shake it. Longer rod might give her more distance casting but normally I find that over played. Watched to many guy with long rods out there trying to reach the boats from the bank and guys in the boats seeming to be trying to reach the bank go figure! A 6.5 to 7 foot rod will get her out far enough.
The rod, reel and line are simply part of a system designed to catch certain sized fish. Seems they are set up as a package to actually catch bigger fish than the average guy want's and not heavy enough for what the trophy hunter is looking for. In the end you will probably find there's no positive answer in buying a rod and reel, just get what you are comfortable with. Start inexpensive and as mom grows with fishing she can decide it she wants something else, it really more personal choice. Some guy's never get beyond "good enough", that would be me, and some guys seem to think nothing is good enough till they get the best there is, that could be anything but generally that falls down to personal choice backed by experience! I believe that best doesn't exist in any product. Best is usually simply a state of mind that different people have. Best for one guy may not be for another. Don't chase best, to get there you will spend more money that needed and might end up not even caring for what you end up with.
damn, got carried away. Didn't mean to go on like this this long!