Ok check out page 41 in the Lizardmen book Fig: 2 Notice it says that the starting formation has +2 rank bonus. you will notice that the first rank is all skinks, the second rank has 2 skinks and 2 kroxigor, the third rank has the same 2 kroxigor and one skink. Also notice that a rear rank cannot be wider than a front rank. also notice the Spawn Kin rule on page 53 where is says that Kroxigor are always placed in the second rank.
at least your trying but I've never said anything about most of those rules. all I've said is that while the rules say they're always placed in the second rank, they obviously aren't. theres can be instances where you have them in the front rank, and instances where they're in the 3rd rank back.
Counting ranks for rank bonusses is completely separate and different to the rules for working out who can have supporting attacks. Calculating depth of ranks and width of files is calculated as equivalent ranks or files of smaller base size in unit. In main book only should be used when larger base is exact multiple of smaller base; in Lizardmen book use the smallest base and don't worry about exact multiples as you round up to next larger base size that is an exact multiple. Supporting attacks are based on whether a model is directly behind a front rank model not whether it is in a rank that counts as 2nd, 3rd, fourth or whatever rank for rank bonusses. Bonusses count rank equivalence; supporting attacks count actual models. Re. kroxigors, if you go by strict RAW then the rules only support krox in the 2nd rank of a skrox unit, only allowing krox into the first when too many skinks die to maintain a full front rank. While it never says specifically that you cannot place a krox in a third or fourth rank, strict RAW says that these ranks are disallowed by the specification that they have to go in the second rank. I.e. your unit has to be at least as wide as the total width of krox with all the krox in the second rank unless there aren't enough skink to allow this. This rule would apply at the beginning of the game at at any point the unit is reformed. This probably should have been amended in the changes to the rules which removed long reach. To keep the original spirit of the rule then kroxes should be allowed to stomp from the second rank and supporting attack from the third. I.e. they should still count as in the first rank when in the second and the second while in the third, after all they are at least 3 times bigger than the skinks at their knees.