Sorry to hear of your loss. It's difficult regardless of whom/what is lost. The take-home from this is that you do have those fond memories and that special place in your heart. Having a new pet, especially after the loss of one, doesn't necessarily mean you have to 'replace' the former, or 'replace' the memories of the former. [We] lost our dog circa 3 years ago and my mam was unsure whether she'd get another one, as they were inseparable. Fortunately, she found some resilience and was able to contact the breeders we had ours from. Luck would have it that the bitch had just been covered and we were in line for one of the new puppies - mam had her reservations as she didn't want the new pup to be (too) dissimilar to the old.
What we now know is that they're worlds apart, but both have a special place in the hearts and minds of my immediate family. They both have their quirks and both are truly loved.
I hope you're feeling okay, given the circumstances, on behalf of us all at TSR. I'm sure you'll grow to love the new Guinea(s) like you did the old, and please don't feel you have to replace the former. Difficult though it may be, attempt to celebrate the life of, rather than mourning the loss of.