The blocks would by default have the properties (hardness, minimum mining level, and flame resistance) that the full blocks have.

Specifically, while playing the BlastOff modpack I used a lumber axe on a tree (on dirt that I had on top of my base) that didn't have leaves on top, so it broke all the wood blocks in a 3x3x3 cube. Even though the carpenter's blocks had materials that required a pickaxe, the carpenter's blocks were still harvested.

Assuming the tool respects harvest levels on blocks, I don't think this behavior would ordinarily happen. If you just check against a block's static material, on the other hand, this type of behavior will happen. It's similar to the way mini-map mods work - they'll do what's fastest, not what's most accurate. Though I don't know how that particular mod detects logs for removal.

As for changing the frame material, the only way to get around this is to create new variants of ALL the blocks and specifying iron-type material. Kinda messy.