I'm so, so sorry for your loss. I understand you so well, I lost a young dog (Irish setter) many years ago and for 16 years I was so traumatised that I couldn't even think about getting a dog. I cried for a month every day and was depressed for several months. When my husband first brought up the idea of getting an English bulldog, I said NO WAY, we stay in China and with the veterinary services available here, I'm not gonna get a dog with such high medical needs. I don't want to get through this pain again. But then I started to look at EB on the Internet, when I bought myself MIni they gave me stuffed toy...I found this forum...and couldn't resist. And we got an EB, and he brought so much laugh and joy (and problems, of course) into our life... I never had such an amazing dog! Nothing is better than having a bulldog.
Despite your pain you must face two irrefutable facts:
1. Since you've had a bulldog, you never want to live without bulldog
2. One day when you feel like getting a bulldog, what can be better than having a bulldog from good parents and even, better, from your own boy? Nothing.
So, I don't see any other choice for you besides from taking a baby into your home. It's a great opportunity to have a baby born from your precious bully. And it will be a therapy for you and your children. You will be busy with puppy potty education (being busy always helps!) and your kids will just enjoy him.
Again, my heart is very sore for your loss. Will keep you in my prayers.