There's red flags all over this to be honest.
OP, in the nicest possible way you sound a bit clueless, and like it's been a bit of an impulse/got carried away with everything kind of circumstance?
There's nothing much out of the ordinary with the breeder, except she sounds like she breeds on an industrial scale and caters for people who are, well, a little bit clueless and therefore she gets away with the bare minimum. This suggests she runs very much as a business and not for the love of the breed/dogs.
Children going to meet the pup is an absolute must and I would insist on this too as a breeder. Also, the deposit as people are awful and mess breeders around. The £700 overall sounds about right before collection, but WOW, £2500 is a huge amount for a puppy.
Poodle crosses are unpredictable to how they'll turn out, and to be honest it's very much a trend and a not great one.
Miniature poodles are lovely little dogs, and worth looking at. Alternatively, one of the lapdog breeds like a Lhasa or a Bichon would be worth looking at if you want lower exercise requirements. A lot of breeders of pure bred dogs do so for the love of the breed and the dog, and would be only too happy to talk through any concerns, and tell you all about their breed. Going to Crufts is a good idea to discover about the different breeds.
Puppy training and finding someone knowledgeable to mentor you is a MUST.
Those advocating a rescue, in a perfect world yes, but sadly a lot of rescues have severe behavioural issues which yes, are human caused but makes them highly unsuitable for novice owners. Our town is full of rescues who are reactive, have separation anxiety and need a lot of remedial work from experts, not the novice owners they've ended up with who love them, but cause them more anxiety and issues sadly.