Racial substitution levels + ACFs interaction

[rrwoods]

If a racial substitution level doesn't list a class feature, can an ACF replace that class feature?

My reading says no. The rules for substitution levels as present in Races of Stone say "the class features of the substitution level simply replace those of the standard level" and "you give up the benefits gained at the level of the standard class and you get the substitution level benefits instead". Others here have said that if the sub level doesn't say you lose something, you don't. What is the support for that reading?

[Soranar]

Ìn each case, a substitution level or an alternate class feature may , or may not, have a cost.

The cost for each trade is indicated (this feature replaces X class feature)

If there is not such clause listed, you get the extra feature for free as long as you meet the requirements (usually the requirements are alignment based or race based)

So yeah, you can totally use several different class features and subsitution levels as long as they don't interfere with each other

[rrwoods]

What's the text support for that?

Goliath barbarian's mountain rage feature does indeed have a sentence stating it replaces rage. But I don't see anything in the rules for substitution levels (in RoS) that indicates that a substitution level always says what features it replaces. In fact, as I quoted, there's text that seems to indicate it always replaces all of them.

In addition, Goliath Druid's first level explicitly lists wild empathy and nature sense, which they wouldn't need to list if they weren't otherwise lost to the substitution level.

[OldTrees1]

1) Racial Substitution levels only replace what they say they replace although sometimes they list everything for completion (which indicates inconsistent writing conventions). -citation needed-

2) You can only use an ACF if you still have what it trades away.

If the substitution level does not have a feature you cannot trade the missing feature away for an ACF. However you can trade a feature that still exists (say Spirit Lion Totem ACF with Goliath Barbarian 1 substitution level).