I co-slept and breastfed both my kids. So as not to wake hubby, we have a futon mattress on the floor of our room... and that is where I co-slept with my kids and nursed them during the night-time wakings. It worked for us. When my kids were babies... I co-slept WITHOUT blankets. I just kept a bathrobe on me to keep warm. And our baby was always dressed per the weather. Once my kids got older, and even now, well we "can" have blankets & co-sleep...but I am still careful & wake during the night to check my 2 year old, just in case. My son now naps in his crib in our room, and at night on the floor futon with me. It is a flexible "habit" we have and it works for all of us.
I would say, that a memory foam bed is "not" safe for a newborn... these mattresses form a 'mold' around a person's body. It could easily form around her body/head and not allow breathing.
As for your cats, this is also a POTENTIAL hazard. I have heard of pets sleeping right on top of a baby... unbeknownst to the sleeping Parents.
Yes, co-sleeping is partly a convenience and a choice of raising our babies, which many cultures do, in light of "attachment parenting." BUT, still, I think you have to keep in mind the "potential" hazards to a newborn... THIS should be the foremost priority. Not the convenience of others.
For us, we used a "Moses Basket" for our son... he fit it until about 3-4 months old. It was great and I could put it wherever I was sleeping. NO matter what... with breastfeeding, you will still need to (1) wake (2) get baby no matter where they are sleeping (3) nurse him/her (4) put them back to sleep. So no matter what or where you nurse... it is STILL a "waking" for you.
Also, there were times when I would be nursing my kids during the daytime while sitting in a comfy chair with a boppy pillow... and I would inadvertently fall asleep WITHOUT knowing... right there! And it scared me, because the baby could have easily fallen off the Boppy Pillow, as I slept. Remember, a Mom often has lack of sleep, and you could potentially fall asleep AS you are nursing and NOT know it... so you'll have to MAKE SURE baby is in a "safe" position, not under covers/blankets, back in the bed-sleeper-cradle thing, and then make sure Hubby is not in the way etc.
Another thing is, your Hubby is a sound sleeper as you say, and moves around a lot... so I would make sure that you have a BIG enough bed for all 3 of you to sleep in. Otherwise, Hubby could easily bump into the bed-sleeper-cradle thing IN the bed or jostle it off balance tipping baby over or waking him/her.
To keep the cats out of your room while you and baby/Hubby sleep... perhaps just keep them out by closing the bedroom door. Also, you don't want cat "germs" getting on a newborn... cats have kitty-litter on their paws etc., and their dander can perhaps irritate a young newborn.
REALLY think about this per YOUR situation... co-sleeping is great... but no matter what, the safety of the newborn/baby has to come first. And yes, there have been infant deaths due to suffocation or pets sleeping on them, and in my state there have been incidences of a baby dying because a Parent rolled onto them and didn't even know it. *Suffocation is a "silent" death.... you can't 'hear' someone suffocating, much less in their sleep. So if you have baby in bed with you...you will also perhaps need to forgo having bedding/covers/blankets on you, and/or even a pillow. SIDS is an issue until about 6 months old... some say more.
All the best, just some thoughts to keep in mind,
Susan