To remove the - you need to edit the font itself to remove the actual character of -.
For the killstreak you edit the visible and enabled values of the huditemeffectmeter_killstreak to 0 for everything.
Also these in autoexec for the other killstreak element.
cl_hud_killstreak_display_time "0"
cl_hud_killstreak_display_fontsize "0"
cl_hud_killstreak_display_alpha "0"