The first seems like a simple jutsu with not that many battle applications. It's useful for transporting people underground but isn't as effective in battle as the previous jutsu used to travel underground in my opinion. Though outside of battle it could be useful for traversing the ninja world.Pretty much I agree with all you said. The 3rd I like for obvious reasons lol. Moving on.
(Doton: Ton'neru chika no Jutsu) - Earth Release: Tunneling Technique
Rank: C
Type: Supplementary
Range: Short - Long
Chakra cost: 15
Damage points: N/A
Description: The user after performing the required hand seals Ram → Dog → Rat → Bird is able to create a wide tunnel in the ground, this cannot travel through rock though or anything with a high density. The large tunnel that is created allows the user to transport others without detection.
Note: The initial entry of the technique is short range.
(Doton: Dōka Iwa fubuki) - Earth Release: Assimilated Rock Blizzard
Rank: C
Type: Offensive
Range: Short
Chakra cost: 15
Damage points: 30
Description: After performing the Assimilate All Creation Technique to fuse with an object, the user controls the rocks that make up their "body" and shoot the rocks at the target.
Note: Must use Assimilate all creation technique beforehand.
(Doton: Retsudo Tenshin) - Earth Release: Violent Heavenly Earth Needle
Rank: C
Type: Offensive
Range: Short
Chakra cost: 15
Damage point: 30
Description: The user after after using earth release: earth flow wave, will perform the snake hand seal and then will create a large needle out of it to impale the opponent.
Note: Must use Earth Release: Earth Flow Wave before hand
The second is basically just an offensive jutsu used after another jutsu. That allows you to fire the components of your body. It could be used to aid in Taijutsu if you use the prerequisite technique but isn't widely useful outside of that application I believe.
The third is pretty much the same as the second though it's individual use would be against an opponent who rushed you or tried to destroy the earth wave you were riding.