Killian Tillie's body is problematic as a front court player. He should be picked in the 20's or late teens.
Bol Bol and Porzingis are not a like. Bol Bol is a plodding big that will never be a able to play PF. There is a reason why you don't see players with his body type succeed in the NBA, especially when they move like that. I also don't love the form on his jumper, but that holds no weight on my evaluation of him as par as his projection.
Bol Bol will get pushed around in the NBA and will not be able to put on the weight to compensate.
I think you are forming your views on Bol Bol just through watching his highlights.
I think Tillie has a pretty ideal body for a modern 4 with good enough feet to switch 2-4.
Bol Bol will absolutely get pushed around in the paint, which is why it makes sense to pair him with a guy like Zizic (sort of like how the Knicks paired Porzingis with Kanter, though Zizic projects to be more versatile than Kanter in the long run). Bol would focus on shot blocking while Zizic focuses on rebounding, so both are playing to their strengths. If he shoots the 3 well in college, I think he'll rightly go top-10 in this draft.