red green and blue are effective against 3 colors and weak against 1 only, all colors have the same amount of strong, weak, and normal damage
you can check that by playing weak levels with different colors monsters and having a rainbow team to test
As @Expired said there is no difference in the number of colours that each colour is weak / strong / normal damage against. The difference is more subtle that that - with RGB the colour you are strong against is not the colour that is strong against you unlike purple and yellow. How this effects play is that an RGB tank not only gets hit harder by its ‘nemesis’ colour but it hits back weaker where as yellow / purple both hit hard vs each other
That is wrong information. Special skills are not colour specific unless otherwise mentioned. So Justice would do the same amount of damage to heroes of all colours, unless one of the heroes is already hit by Guardian Jackal. Similarly, Azlar will do same damage to all heroes, irrespective of colour, unless three of the heroes are previously hit by Guardian Falcon.
The amount of damage done by any hero special is purely calculated by the ratio of the attack stat of the attacking hero to the defense stat of the defending hero raised to the power of 1.35 and multiplied by a random number. So no matter the colour hero specials will always do damage based on this particular formula. The only exceptions are the elemental buffs/debuffs. For example, if Evelyn hits a hero then that hero gets reduced defense against green, and if Lianna fires immediately after, then she will do more damage than usual. Similarly, Gravemaker does extra damage againts green heroes because it is explicitly mentioned in their card.
This is a common misconception among lot of players.
That is correct. So unless you have an elemental debuffer on your defense (or a hero whose special is “strong against X” like Hel and GM), your color focus in setting up a defense is purely on managing the inbound tiles.
The real advantage of Yellow/Purple pairings on defense is that there’s no attacking tile color which is strong against one member of the pairing and neutral against the other. This is unlike Red/Blue (Blue), Blue/Green (Green), or Green/Red (Red).
Minions take on the color of the hero they are cast on. For all intents and purposes, minions behave like relatively weak tiles sent by the hero they are cast on when attacking.