Q 120: Why can the Improved Cold Endurance feat (Frostburn) be taken up to 3 times, but the Improved Heat Endurance feat (Sandstorm) be taken only once? Just because the writers didn't feel like being consistent?
Q 121: What other ways are there to increase Fire resistance via a permanent ability (feat preferred, but low-level class ability may be ok)?
There is the Forgeheart feat from PGtF, but it's dwarf only, and there is the [Improved] Fire Heritage line in the Planar Handbook, but that's all I could find.
The goal is to apply said abilities to Goliath to make them Half-fire giants for a norse campaign homebrew setting. I could just rule that Improved Heat Endurance can be taken 3 times, but if there is a simple way to just take one other feat, I'd prefer to use that instead.