The above is from Sec 416. (the bold items are my emphasis and commentary)
Basically is says that if Safe Harbor is the SOLE funding method (other than deferrals), then the plan is NOT TOP HEAVY. If the plan is not Top Heavy, then, of course, no minimum is required.
So, in your case, if the SHM is the ONLY employer money (or, more specifically, the SHM and a discretionary match that together satisfy ACP Safe Harbor), then your plan is NOT TOP HEAVY, regardless of the key assets held.
Picky point: Safe Harbor doesn't satisfy TH minimums (if the SH is the only ER contrib); the plan is simply not TH in that case.