Usually, when you travel abroad with your pet dog, having adequate rabies antibody titer is one of the requirements. If the pet does not have recommended titer, then it is routine to give one more shot of anti rabies vaccination even before the one year completion. So, in your case, yes, you can give Vaccination before one year.

Yes anti-rabies vaccine can be given one year before the first dose, there will be no issues just ensure u are getting vaccination done under the supervision of a veterinarian

Yes, you can give it before 1 year to your crossbreed Maltipoo. Usually, during post bite cases, we do that. But to achieve the required titer (or you can say the required effect) in the dog, it requires time. To travel abroad, you need to have a minimum level of serum titer, tedted by an EU certified laboratory. Hope this helps. Thank you