Will this year be a lucky one?

If it was the other way around, you being fraternal twin rabbit and your wife a pig, I would say this is THE year for you two to have twins. With the way it is now, if you don't want to wait to try during the year of dog to have a pig baby or during the year of pig to have a rat baby, I would say this year works better than the next few years. My suggestion is to try after July. I, myself, like twins the best, so I hope you are successful in giving life to a healthy pair. Good luck!