#3, the loud/quiet/register options, I like it. +1

Your #1 point about the length and/or speed of a fade out is a request that appears here frequently. I've heard of at least one workaround [without using audio editing in BIAB or elsewhere] by reducing the number of beats per bar so volume (or tempo) changes can be made more frequently. I believe the main solution someday is to support non-integer fades and tempos. Absent that, allow changes of volume and tempo more often than a measure at a time, on the beat level.

A couple of wild guesses if I may, about #2, the pops afterward, which may deserve its own post:

Sometimes I extend the length of a song and use a 'stop' chord like C. to be sure all sound ends.

Something you can check if you hear a 'pop' or 'thunk' type sound is, do you have the song looping on? You might be hearing the song begin repeat, with something on the drum track. This has been noticed in the past on a few earlier versions of BIAB. Mute each track and see if you can isolate the offending sound. If it is guitar, then I don't know, but it's not unheard of for an individual RealTrack to have spurious noise on it, and if you report it with an example recording, they can find and fix it.

Or it may be none of these things. Can you tell us which version of BIAB you use? Can you post a link to an audio recording of the problem you are hearing?

BIAB 2026 Win Audiophile. Software: Fender Studio One 8, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Presonus Quantom HD8 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.