Here I will contain real facts about the 3 characters.
Mongolian Golden Eagle.
The Golden Eagle is one of twelve species of large predominantly dark-coloured eagles in the genius Aquila found worldwide; a large brown bird of prey, it has a wingspan averaging over 2 m and up to 1m in body length. Adult Golden Eagles range widely in size across their range. Length may vary from 66 to 100 cm, wingspan can range from 150 to 240 cm, and weight is from 2.5 to 7 kg.
I will edit the Size to suit are film.
Eagle Size in Meters then changed to feet.
Wingspan 2 Meters
Body length 1 Meter
Wingspan feet 6 Feet
Body Length 3 Feet
Body length 1.3 Meters
body length 4.3 Feet
Body length 0.45 meters
Body Length 1.5 Feet.
The Mongolian Eagle looks like Its American Cousin but without the white head dress and a slightly more dark brown.
The Wonderful Marmot
And all of the three guys together.
If anything is wrong please let me know roughly you can work out the sizes, The eagle may be a tad lage once the final eagle drawing is completed, Ill replace this rough one.