Hi, I just wanted to add some support really. Sounds like you are a lovely mummy planning ahead for the hard times
Your DD is lucky to have you
On a practical level the only thing I think you can do 'wrong' during SA is to believe that your child is being manipulative or in some way bad and that leaving them alone with their anxiety will some how toughen them up and get them used to being without you - and it sounds like you are the total opposite of this so there is nothing to worry about. IMO you can never give your baby too many hugs or pick her up too much, yes you might fear habits etc but ALL of those things can be undone if necessary. Often the more you be with them during SA the quicker and smoother it goes, they are reassured that you will always be there and will then need you less as their confidence returns. During A time this might mean taking her to the toilet with you, offering her to come with you every time you leave the room, planning in advance so that you need to leave the room less, making some easy meals and letting the cleaning slide for a few days just so you can spend as much time very close to her as possible. With nights I've sat in the room half the night, laid on the floor by his cot with my hand on him, even climbed in the cot and slept there with him! Not very comfortable for either of us but at least he knew I was there. I have always found that as soon as soon as the SA passes he goes straight back to independent sleep with little or only slight encouragement. He has even signalled for me to leave him alone so he can sleep!
I think SA is the hardest when you fight it. If you can kind of give in to it and roll with it for a few days it is so much easier on everyone.
WRT DH putting her down to bed, sounds like a good plan to at least let him see how you do the BT routine and put down and I agree with katy that there are times when it is hard work having someone else to take some of the strain is great, but I also think if you are all happy with your set up then that's fine too. My DP has only put DS to bed maybe 3 times, each time when I was very very ill, I was surprised that either of them managed but they did - when needs must. He did nap time once or twice per week in the last few months before the nap was totally dropped but BT PD has always been my thing, and I expect it will remain so for a long time to come (there are other ways daddy's can support mummy's and help reduce the strain if bed time is not their thing - picking up some other household chores or cooking for instance).