In a vacuum, Meikle is a solidly better defender than Dawson at the 2 because of the huge DEF gap and a much better defender at the 3. SPD matters relatively more at the 2 though. A guy with 59 spd like Meikle (who brings nothing else to the table) should never be playing at the 2 on a D1 NT team though.
To make up for 23 Def, 2 letters grades of IQ, and 12 points of ath purely from a defensive perspective you'd theoretically need a speed difference of between 65-70.
always have to check out the rest of your team before I respond, since these questions are impossible to answer "in a vacuum" because there is never a situation that is actually in a vaccum.
I found that the SF (meikle) is a mid-tier skill SO with 83 WE and the SG (dawson) looks like a top recruit who could be really good with good but lower 65 WE.
Your team is not that competitive for an NT spot anyways so I would definitely start the guard (it's not close). Killeen and White are better options than both of them. So I think Killeen, White, Dawson should start. I'd stick Dawson at the 3 for sure given the low BH/PA/IQ. And I like starting freshmen at the 3, it's less defensively intensive than the 2 against the average team (especially when you don't need to worry about the 5 star SF teams who you will lose to anyways)>
Speed is really, really important at the 1/2, probably twice the amount of ATH. As Hockey outlined, Meikle is a solidly better defender than Dawson at the 2 because of the huge DEF gap and a much better defender at the 3 (since his speed deficiency means less). But Killeen and White are two of your best players and Dawson must be started for development reasons (he'll be much stronger than Meikle at the 3 defensively soon enough, probably by the end of the season).
I know you just asked a defensive question but note that Dawson is an elite shooter (good for 7-8 PPG even as a FR) and Killeen brings nothing on the offensive end. You have no guard depth so Meikle should be deployed as a supersub at the 2/3. No idea who your backup PG is. It should probably be White. You should to design your depth chart so if Meikle and Dawson are on the court at the same time Meikle plays the 3 and Dawson plays the 2. I can help with that.