The essential rank of classical groups

Let G be a finite classical group defined over a finite field with odd characteristic. Let r>2 be a prime, not dividing the characteristic, and D⩽G a Sylow r-subgroup. We consider the Frobenius category FD(G) and determine the cardinality of a minimal conjugation family for it. This amounts to determining the number of G-conjugacy classes of essential subgroups of D, that is, the essential rank of FD(G). In addition, we characterise those classical groups which allow an r-local subgroup controlling r-fusion.