Everything you mention will work for creating a backing track within RB. If your project happens to be a pre-existing song, find a good midi file, import it and let it serve as your foundation. No need to re-invent the wheel, so to speak. A good midi file will accurately reproduce the sounds of the original song in most cases.

While you can easily enter notes into RB using a midi keyboard, controller or similar, if you have a keyboard that will 'save' a midi file, the easiest thing is to create your midi version of the song using the keyboard, saving the file to a flash drive and then open the midi file in RB.

To address the things you can't physically play in tempo or for any other reason when your personal keyboard skills are less than stellar, use a friend, relative or acquaintance or hire someone with the skills. A competent player will have the skill and probably the tools and knowledge to pop out a midi file of a song in just a few minutes time.

Opening a midi file first should populate the chord chart, set the key signature and tempo for you and create a tempo map so the RB tracks you generate will be in sync. This will be true regardless if the midi file is a commercial release or one you've created yourself. The bottom line is to me, there is no easier way to enter notes, chords, tempo and key than to use a midi file. I think that inputting notation allows you to create more complex arrangements than some of the other methods. I personally don't have the knowledge and skill to do that so it's speculation on my part.

BIAB 2025:RB 2025, Latest builds: Dell Optiplex 7040 Desktop; Windows-10-64 bit, Intel Core i7-6700 3.4GHz CPU and 16 GB Ram Memory.