I have never tried it with bactas, but using the "wait" key you should be able to override the respawn-delay of items. A value of "1" should have the item respawn within 1 second. I am not sure if values lower than 1 (such as 0.001 or -2) work, but I am certain that "0" will use the default time and "-1" prevents the item from ever respawning. Maybe you can figure something out with this to decrease your bacta-count, yet giving players access to enough bacta to complete your challenges.
In case fall-damage is one of your issues: I am not sure how to do it, but you can use shaders to mark surfaces as "no falldamage" surfaces. Acrobat usually does that on her jump maps, preventing falldamage even on basejk servers that have falldamage enabled.
No need for additional mods.