Growing up my family kept guinea pigs for years. My dad was highly allergic to cats but fine with the pigs, as long as the cages were kept clean. Only way to know is to the handle the pigs yourself at a breeder or pet store.
Things to keep in mind:
*They are some of the sweetest,cuddliest rodents accross the board. It’s very rare that they bite, they are social animals who like interacting with their owners (as long as they’ve been handled enough when young to not be fearful of humans), they generally like to be held, they love to be stroked and even ‘purr’, etc.
*Since they are very social animals (with adorable social behaviors) and it’s best to start with two or three. I think it’s cruel to keep them singly.
*Unlike rabbits (which can be litter-box-trained) and most pet rats (mine never, ever pooped on me and rarely did more than leak a little pee), it’s very difficult to teach them to control their bladder and bowels. They will flood you with piss when you are holding them (I always carried mine in a towel), and if you let them loose in the house, they will just go wherever they walk. They drink a lot of water and they poop (moist droppings) and pee a LOT. Lots of waste means lots of work to keep their enclosure clean, healthy for them and non-stinky for you. This is the major drawback of guinea pigs, for me.
*They are rodents and they will chew anything. If they’re going to be loose in the house they need close supervision (and you better not have carpets, because of the peeing and pooping and stepping on the squishy poop).
*They are the noisiest caged mammals you could keep. I find the noises adorable but they talk all the time, have a whole bunch of cute sounds they make, and can squeal VERY loudly (usually when they are anticipating treats).
*I don’t see them properly housed in most cases, but ideally they should have an enclosure/cage with as much open floor space as you can possibly manage. Guinea pigs LOVE to run and will stay healthiest if they have the opportunity to be very active. When kept together in enough space they frolic and chase each other all day… it’s adorable. The happiest pigs I have seen were those who were kept outdoors with a large fenced yard area (and hutch/coop to take refuge in), or who had half a room in the house sectioned off for their use.
*For a small caged mammal, they have a decent lifespan - all of ours made it to at least 7 years (and the oldest to 9). A much more long-term investment than a rat, gerbil, hamster.
Honestly based on what it seems you’re looking for, I would recommend a pet rabbit (or two - they are often available in shelters as bonded pairs) instead of guinea pigs. They are cute, come in a huge array of sizes and varieties, are easier to keep solitary (many are aggressive towards the same sex, or even all other rabbits), quiet, have less of a need for exercise, can be quite affectionate, are easily trained to go only in their litter boxes, can be left loose in the house - some chew what they shouldn’t, some don’t - or kept in a limited area like the kitchen.