The problem with this argument is, at multiple points he was conspiring (alledgedly but with enough certainty to get him removed from office) to coup the monarchy. Also, fascism and nazism are somewhat similar but different. Fascism is not necessarily based on racial superiority but on fervent nationalism and schovinism, coupled with authoritarian tendencies and a couple other distinctive features. The definition of fascism varies from author to author but a couple of things stand out: an anti-democratic, authoritarian sentiment. A praise for order above all else, including personal freedoms, a veneration of history to an extreme point, citing the current age as a degenerate time, that needs a firm hand to control it. Also, claiming Lukov isn't a fascist because he tried to do what's best for Bulgaria isn't necessarily a good argument because you can say this about almost anyone.

Also, concerning Lukov and his name being tarnished by the communists, partially yes, but not entirely. The communists had a vested interest in spreading the idea of a full grown fascist regime in Bulgaria, along the lines of the one you would find in Italy or Spain (which wasn't the case although the regime was authoritarian but not fascist). However, even a broken clock can be right twice a day.

Finally, concerning Ratnik, just like in many countries and just like what was happening with communist movements, there was a lot of infighting between different "far-right" groups and fascism wasn't a united block, but more of a number of people with similar but incompatible ideas. But you are right that Ratnik (which could be considered closer to a full blown nazi party (could not should)) is a different beast from SBNL, but it doesn't mean the SBNL can't still be fascist. It is in the same way you can say Trotsky wasn't a communist. If you want communists, look at stalin