Some things I can Say about that: First of all you seem to use the movies as reference. The books give only limited information about numbers but the films even less, so the books should probably be used. So I will not only give details you don't already know but also corrections.

Helms Deep:
Eomer is among the defenders. The relief force is lead by Gandalf and Erkenbrand and consists of infantry, probably levies and dismounted survivors of the second battle at the fords of Isen. And of course Legolas was the only elf around there.
The attacking army was indeed 10000 strong, but did consist of Uruk-Hai, normal orcs and Dunlendings.

The siege of Minas Tirith:

The defenders of Minas Tirith:
From Gondors fiefdoms came:
Forlong with 200 well-armoured men with battleaxes
Dervorin with 300 footmen from the Ringló-vale
Duinhir with his sons Duilin and Derufin and 500 archers from the Blackrootvale
Prince Golasgil with his small personal retinue and a large number of ill-equiped armed civilians from Anfalas
Some leaderless highlanders from Lamedon
About 100 fishermen from the mounds of the Anduin
Hirluin the fair with 300 warriors wearing green from Pinnath Gelin
Prince Imrahil with a group of fully armoured knights on grey horses and 700 tall infantrymen from Dol Amroth
Alltogether less then 3000

Relief force:
From Rohan:
6000 riders of Rohan, all mounted, including Theoden as Commander in chief, Eomer (first marshall of the Riddermark), Grimbold (second marshall of the Riddermark) and Elfhelm (third marshall of the Riddermark) as the most important other commanders

From the fiefdoms:
the grey company, led by Aragorn, containing Legolas, Gimli, Elladan, Elrohir, Halbarad, around 30 rangers in total (all on foot)
Angbor the fearless with a large number of men from Lamedon (probably dismounted due to travel by ship but origanaly mounted)
No army of the dead! They were released after capturing the black fleet.

The battle of Dale
Commanders of the defenders:
Dain II. Ironfoot, king under the mountain
His son Thorin IV. Stonehelm
King Brand of Dale
His son Bard II.
After the deaths of Dain and Brand their sons took over command and retreated into the mountain until the ring was destroyed and the resolve of the besiegers wavered.

Lots of numbers are of course unknown and I just summarized what I remembered our what I could check reasonably fast, as I was just referencing the first chapter of the Return of the King for other reasons.