Editing notes in midi files note by note is known as step editing. On drum machines like an Alesis SR18 they have a built in step editor but I quickly found it’s not much fun working on hardware drum machines from an LCD with menu buttons looking for a kit sounds and time stamps. Step edited midis also tend to always sound like a robot or machine gun with quantizing and require a lot of manual tweaking that may end up in the end still sounding like garbage. Midi editing using software is the answer to that and much more flexible, but it is an an investment in time etc. for that flexibility.
To avoid editing midi’s, loop packs are your friend, but as noted they need to be compatible. GrooveMonkee loops can now be used the same way as the BB content. To have a simple, no editing, audition of loops you could use BBM to create audition songs and load a bunch of main loops from BB or GM packs per genre etc. Setting just the main pattern, or adding compatible fills per part, you could start the audition song with song parts (each pattern to audition) controlled by the pedal instead of fiddling with knobs to select songs and audition different patterns by transitioning from part1 to part2 etc. The below shows a project loaded with new songs arranged just for auditioning. I’ve found that the last thing I want to do is edit midi’s until after I’m sure I don’t have a loop that already does the job and I’ve probably paid five times what the BB cost for loop packs over the years while working with software to be sure I do as little as possible midi editing up front to get the main parts of a song nailed up. Better to have one good beat all the way through than never get to play because you can’t get a step edit to sound good. I think of editing of existing midis as enhancements to vary fills etc based on a good pattern, not the start of how to get the pattern.