True Flame Sorcerers

[Valo65]

Can a true flame sorcerer start off as a sorcerer and then multiclass to another spellcasting class, such as cleric or druid?

I assume they cannot use non-evocation spells from these classes' spell lists, what about their evocation spells? Also, can true flame sorcs use the non-spell abilities, such as divine might, divine shield, smite evil and wildshape?

[Twily]

I've not done these exact things, but I did have a true flame Sorcerer/Cleric, They could cast evocation cleric spells and could use the feat based domain abilities.

As a result, I suspect they can multiclass, can't use non-evocation spells, can use the evocation ones, can wildshape, divine shield, etc.

[Barradoor]

They can multiclass
They can use druid shifting (It is a feat-type thing, like epic spells).
They can only use evocations; Potions, Wands, the like.
They can only cast evocations of their respective multiclass, non-infinite.