The latest report I have for Heth's Division is dated August 18, 1864 so by the time of Five Forks these numbers would be substantially reduced. But for what it's worth:
Kirkland's Brigade: Present for Duty Aggregate 1593 (1491 Enlisted Men)
Davis's Brigade: Present for Duty Aggregate: 1131 (1030 Enlisted Men)
Cooke's Brigade: Not Listed
Fry's Brigade: Present for Duty Aggregate: 1516 (1370 Enlisted Men)
The "aggregate" includes general officers, general staff officers, and field, staff, and company officers. In the 2nd Mississippi's case...the only regiment I really have confidence reporting on...it was reduced by about 1/3 between August 16th, 1864 (149 aggregate) and when it was surrounded and surrendered during the Petersburg Breakthrough on April 2, 1865 (the 2nd Mississippi surrendered some 99-100 men at Hatcher's Run).