Risks of 2 new young puppies from different breeders:
Neither puppy has had their first set of shots** Reputable breeders especially will keep their toy breeds until 12 wks - which means around 10 wks they have their first set of shots.
Dr Jean Dodds has a vaccination schedule it should be found in the library.
I advise you to look up this schedule and talk with your vet - ask for her recommendation on how long to wait before bringing in the second puppy.
**Insurance**- most companies wont start the insurance until the puppy is 8wks old.
Double the trouble
Which I expect you are aware of. Training, housebreaking and financial costs.
Good luck with your new pup(s)