What are all the types of ranks in Mario and Luigi Bowser's inside story?

Answer 1

Mario and Luigi:

Mushroom Rank: Level 1

Shell Rank: Level 6

Flower Rank: Level 12

Shine Rank: Level 18

Star Rank: Level 25

Rainbow Rank: Level 40 (Secret)

Bowser:

Gold Rank: Level 1

Silver Rank: Level 10

Gold Rank: Level 20

Final Rank: Level 40 (Secret)

Answer 2

I believe there are these bosses (in chronological order) :

Bowser (Tutorial Fight)(in Peach's Castle)

Midbus (First fight) (No legitimate way to win) (Cavi Cape)

Broque Monsieur (Plack Beach)

Sea Pipe Statue (Plack Beach)

Scutlet (Bowser's Flame Pipe)

Broggy (Plack Beach)

Wiggler (Dimble Wood, Wiggler's Garden)

Durmite (Nerve Cluster)

Bowser's Castle (Giant Battle)

Midbus (Second Fight) (Bowser's Castle)

Alpha Keritin (Flab Zone)

Bowser (Second Fight) (Toad Town Clinic)

Tower of Yikk (Giant Battle)

Wisdurm (Energy Hold)

Bowser Memory M and Bowser Memory L (Memory Banks)

Fawful Express (Giant Battle)

Junker (Peach's Castle Garden)

Peach's Castle (Giant Battle)

Blizzard Midbus (Final Midbus Fight) (Peach's Castle)

Dark Star (Airway)

Dark Fawful (Peach's Castle)

Dark Bowser/ Dark Star Core (Final Boss) (Peach's Castle)

There are also 7 Optional Bosses in the Challenge Node in Bowser's Body.

They are:

Durmite X

Alpha Keritin X

Wisdurm X

Bowser Memory MX and Bowser Memory LX (These two count as one boss)

Junker X

Dark Star X

Bowser X

It should be noted that Challenge Node bosses are significantly harder due to turn limits and increased boss HP

Bosses That are not bosses and Why:

Chakron. This boss cannot technically be defeated therefore he doesn't count

Shroobs. There is a supposed optional boss fight against three Shroobs. I class these more as generic minions than a boss.