Ah now, the thing about the newborn latch is that it is a PITA mostly.
It will get better. The mouth is too small, the sucking muscles aren't strong, you're both figuring it out. I'm sorry to say this but mostly it is practice and time. Even if it is a pain keep trying it lying down.
There are different ways of cosleeping so I don't know what would suit you best. With ds I had a big cot with one side off that was right next to my bed so I just kind of rolled into it and carried on sleeping half in the cot.
With DD I found a way that worked better which was to put a single bed next to the double and dh slept on it, leaving me and the baby in the double.
Cosleeping is safest if started within a week of birth becaue your hormones are all tuned in with the baby and so you are unlikely to subconsciously forget about her or roll etc.
Careful with alcholol intake, as this impairs your ability to be in tune, as do drugs and drowsy medication.
Blankets are best but if you prefer a duvet you can either leave the baby in the centre of the ed and roll to the edge with your duvet, or face baby and tuck it in between your legs and under your arms.
You can have a pillow, but make sure the baby is down some way so that to feed her you kind of curve over her.
She can have a small loose celular blanket over her and the room can be kept warm but not hot. It is better if the mattress isn't too soft either.
To feed it is better in the early days to move towards her, so that you can move back and give her space afterwards. Don't worry about falling asleep though as you'll still be aware of her even then.
Let me know if you have any other questions.