OK, loads to consider:
First - are your DC allergic? Little furry animals and their hay (which is essential for guineas and rabbits) are highly allergenic. My own DD developed an allergy to our rough coated piggies after years of smooth/abby pigs.
Hand on heart, you will be doing the work. your DC might help but it'll be your call.
Pigs need more shelter and protection (has to be dry, draught free and constant. They cannot cope with fluctuations or extremes)
Rabbits are not generally considered to be good childs pets , guinea pigs are (mainly) but they are fragile and they can bite , but its rare.
Phone some Rescues and they'll tell you what size of accomodation you need )bigger is better especially for boars) . I've never kept rabbbits myself.
They won't home rabbits and guineas to live together . Rabbits can kill a guinea pig, their diet is different and they carry a nasty bacterial load which passes to guineas.
Pigs don't need vaccines or neutered unless you want a male/female
Rabbits do need neutered for their health and behaviour and there's annual vaccinations plus dental checks.
You have to get to know them, they hide illness well.
They are vunerable prey animals so you need to protect them from foxes,cats,dogs,birds of prey. Make their house and run like Fort Knox
Our piggies are in for winter they are noisy, their hay gets everywhere and they clang their plates at 3am and eat cardboard (loudly).
We have 3 , we did have 5. DD and I share the work , though I know she's sometimes "Oh Mum can you clean the Pighouse" if she has homework, or out with mates , but I know she will do the next feed or clean.
Rescues are overflowing with them, there will be pigs or rabbits for you. They'll (depending on age) be neutered and vaccinated , you'll need a donation to reflect this .And you get the reassurance that theres advice and if you ever need to rehome them , the Rescue will take them back.
Good Luck 