The traditional parties of the right in Europe pine for the feudal system. They are defined by their attachment to “blood and soil.” They are not defined by any commitment to liberty, economic or otherwise. As much as any socialist, they believe that elites can and should manage society for the benefit of all.
American conservatives are interested in conserving the “liberal” (in the classical sense) system our founders established for us. The brought our country forth to be unmanaged, in other words free. America was the prototype of western civilization's new and improved alternative to the feudal system. It is the essence of everything European conservatives hate.
American style conservatism is beginning to develop a following in Europe. Lady Thatcher was a leading indicator of this trend. But the FN is very much a conservative party in the old sense. There is no hint of classical liberalism about it and a generational change won't introduce one.
These people are not friends or allies of American conservatives and they never will be. They come from an entirely different ideological planet. That won't change merely because a fairly hot looking divorcee takes charge and squelches the FN’s uglier antisemitic element.
Our Left attempts to conflate American conservatives, our Right, with European monarchists / feudalists, their Right.
They are completely different things, philosophically.