It's so much nicer having more than one dog, isn't it; I got Cuba as a companion to my Coton de Tulear, Tycho, after my first Coton, Pamba died tragically young. Tychy was 7 at the time I got Cuba, having had a few years on his own, and has thrived on having another dog in his little life; I do hope your papillon is happy - I have a friend with another Coton (the mother, in fact, of Pamba) who recently acquired a French Bulldog; I'm not sure it's good casting, honestly. I think the way dogs play together is important to get right and some dogs just play differently. At a class once when he was about two years old Tycho played - or rather tried to play - with a pug; but the pug's idea of play was to move off to a bit of a distance and then hurtle at Tycho and ram into his side. Tycho just sat down and refused point blank to play with this little tank. But he and Cuba run-like-hell together, and wrestle and hurtle about side by side and it works beautifully. I should have thought a papillon and a Havanese would be good together. I do hope that that is what you have found to be the case.
Javi and Oreo (my Papillon) play a little differently but Javi has adjusted wonderfully to it. My breeder thinks that Papillons tend to play with more "gusto" then her Havanese. I find that to be true at least in the case of Oreo and Javi...granted it has only been a week.
However, Oreo's play is much more quick and fierce and at first it was a bit intimidating with Javi. Oreo would growl and bark, grab his ball and run at and away from Javi. I think Javi was used to more of a gentle wrestle and romp and chase. At first, Javi would just plop down and look like what the heck has gotten into this other dog but now he chases after Oreo just fine. Oreo is super quick and will get away and doesn't really give the ball to Javi...at least until Javi plops down and then Oreo will roll the ball to him and bark...and it all starts over again. Oreo isn't much of a wrestler...he likes to chase and run away all the while squeaking a ball in his mouth.
Up until he was 2.5 years old, Oreo lived with 2 other dogs (another Papillon and a Wire Hair Fox Terrier) with myself and an exboyfriend. Since then, he has been the only dog for some time and had to endure me getting married and having children.
He gets really anxious if we have gone on vacation and our vet suggested we think about getting another dog so he has another member of his pack with him should we go away. As he has Atypical Addison's disease and doesn't handle stress to well, we were hoping adding another dog would be a good thing. It is definitely an adjustment as Oreo can be crabby and doesn't probably want to play nearly as much as Javi would like (or was use to with his littermates and/or the adult Havanese in his breeder's home) but I think they are both enjoying each other's company and my hope is it will only get better. I do think Havanese and Papillons make good playmates! They are so different...personality wise...but both precious.