Two dogs are twice as much time & money. FYI: dogs (plural) do not self-exercise. So, do you have the time and ability to make sure both dogs get plenty of daily exercise & the second dog gets plenty of socialization (as a puppy and before 16 weeks) as well as basic training during and thereafter?
IMO, it is important you know why you are getting a second dog. It should not be for the first dog (who can be a happy singleton) but for one of YOU. Does the first dog lack something you were looking for (in a pet) or is it devoted to only one person, rather than being equal in affection or a “family” dog?We do not have a crystal ball, but breed characteristics will play a part in how well they do, or DO NOT “get along”. In doing hundreds of rescue placements our group’s advice was to pick an OPPOSITE gender to the first pet, as opposite sex dogs often get along better than 2 males or 2 females. It is harder for two dogs of the same gender to work out WHO will be in charge. Females are often the ‘alpha’ in a mix of a M&F, so sorting out TOP DOG may become problematic in a year or so when the 8 week old, matures into an adult dog. (Spaying will not fix or prevent that.)