A bar across a note stem means to divide the note in eighth. Two bars means in sixteenth and so on. Sometimes dots are added above or below the note to help indicate how many tones that would be. Are such dots available in Finale?
Finale 27 has all types of multiple articulated tremolo markings. You will need to create a new articulation using the default Finale Maestro font. The 4 dot character is number "U+E230". There are double, triple, quad, and six dot versions. Versions with phrase markings, etc... lots of options.