
Working doesn't nessacary mean you can't have a dog but it does mean more planning to make it work.
On the three days you work how long would the puppy be left alone for?
If it's more than 4 hours can you either pop home or get someone to let the puppy out to toilet, feed and play?
Could you take time off work to help get the puppy settled?
If your partner works could that also take some time off after your time?
As for the breed, what is it that's making you consider this cross? You will need to keep in mind if you go for a cross the puppies traits will be more unpredictable, it's temperament could take more after one breed than the other so you need to make sure either breeds temperament would be suitable for you. Poodle crosses don't always have the low shedding poodle coat and the ones who do will require much more grooming to prevent matting.
A very important thing with getting a puppy is to make sure the parents health testing is done with acceptable results. This will be harder to find in a cross breed I'm afraid as there are few good breeders of them about. For the cross your considering if it's a first generation cross (pure bred parents) the mini schnauzer and poodle should both be eye tested clear and the puppies should be eye tested being out of a schnauzer.
If it's a multi generation cross (either both parents a cross or one cross and one pure) if to a poodle the above plus DNA test for pra, if back to a schnauzer DNA tested for Mycobacterium Avium Complex. If both parents are crosses both these DNA tests need doing.