I did 2 issues already. Anyway
Before posting the first issue, I made the Armour Stands (with the tags I used ) hold a spawn egg and a dragon head, The spawn egg was in his offhand, and it is above the normal position (Middle of it's arm) I'll put the command and image below. It was a shulker egg (I got it from a command generator to find out what it was) and I tried to search what number it's data is, but it shows as a dull white spawn egg.

/summon ArmorStand ~ ~1 ~ {ShowArms:1,Small:1,Invisible:1,Invulnerable:1,NoBasePlate:1,NoGravity:1,HandItems:[

{id:spawn_egg,Damage:69,Count:1}

,

{id:skull,Damage:5,Count:1}

]}