The Sedona was completely redesigned for 2006. The 05 and older is a totally different vehicle. Any van 2006 or newer is fine, although there was a short wheel base available in 07 i think? that has ZERO "trunk" space behind the 3rd row, and no 3rd row middle headrest (because its a 50/50 split instead of a 60/40 - it still has a L/S though) so I would avoid that one unless you really don't care about the complete lack of storage. We have an 06 and freaking love it. And yes, all seating positions have L/S belts AND headrests.
LAF - the 06 and newer sedona does not, and has never had a second row bench option. Only 2 captains chairs. The 05 came with a middle row bench though
i love that Kia put L/S belts in all positions 2 years before they "had" to, and honestly, I think it's one of the major, dealbreaker flaws for me about the similar years of the Dodge vans (caravans/town and country). Why have a seating position I can't use? (my kids are all older now, and soon I will have ZERO kids in harnessed seats)