How is Baun different?
No expert but I think the main difference is both Tull and Kikaha were more limited as pass rushers. Kikaha wasn't great in coverage when he played for us and it wasn't something he did a lot of at Washington I think. Tull never really made it on to the field for us in any meaningful way, and if I recall correctly was really only used as an undersized in line pass rusher. Baun is much more versatile and can cover or rush, doing both very well.
Physically, all three more or less the same size. Tull was off the charts in terms of explosive athleticism but stiff/straight line, Kikaha was less explosive. Baun isn't as explosive as Tull, more similar to Kikaha, but certainly faster than Kikaha.
Kikaha and to a lesser extent Tull had more of an injury history. Lack of position flexibility and injuries limited both ultimately.