Bed transitioning

This might be out of normal subject. But I have a 3 and half year old a one year old, that we are looking to get beds for.

My 3 year old has always slept with my husband and I. My one year old has always slept on her pack and play because she could never sleep with anyone.

My husband has found bunk beds to transition both of them to WHILE we sale this ones and we can afford other beds.

I say that we can’t make them transition to one being that’s their first time and then take it away in the middle of their adjustment (thinking that it’ll sale) and then make them go through the process again. I say it’s not healthy for them since they are so very used to one sleeping with us and the other to her pack and play.

He won’t take my word for it, he wants a “professional” to tell him. So can someone that knows what’s going on help us out? What’s your input? If y’all know of articles talking about this can you send me or comment the link?