It had authoritarianism (with many democratic elements in place) since 1926 (way way more liberal than that of Soviet Union, or Nazi Germany). Before that it was fully democratic (though, chaotic).
As for the conflicts you'd decribed, some of them were conflicts without clear aggressor (e.g. Polish-Czechoslovak conflicts of 1918) typical of those times, some were misdeeds of Polish state (annexation of Vilnus and Czechoslovakian Zaolzie in 1938).
As for the conflicts you'd decribed, some of them were conflicts without clear aggressor (e.g. Polish-Czechoslovak conflicts of 1918) typical of those times, some were misdeeds of Polish state (annexation of Vilnus and Czechoslovakian Zaolzie in 1938).