Alter some background tracks for an escape room

I have an escape room business which is based around memory implants and the games are all memory experiments. We have a scary game called Cabin in the Woods.

We use a couple of background tracks that play during the game, and I want to add some more sound effects to them (rain, birds, rustling trees outside, thunder etc.) as well as some jump scary type sounds (screams, stabs etc) to be provided separately.

We also have a ending sound track which we manually trigger to change to when the team complete the game, currently over that background track there is a voice that says "Memory failure" as the memory is disconnecting, but it sounds like the team has failed the game and causes some confusion, so I want to change that to something like "Memory closing" or similar, and have a separate file we can play before hand that will either be "Congratulations, memory alignment is successful", or "Danger! Danger! Memory timeline ended, memory collapse imminent", both to have some sirens/sound effects behind them.

The full workflow once the sounds are create is below:

Looping background (supplied by me) you to add rain/thunder effects (played when teams arrive)
Memory starting (supplied by me) you to add rain/thunder (played when we trigger to start the game)
Main background (supplied by me) you to add rain/thunder (plays during full game)
"Congratulations" or "Danger! Danger" track to play over the background when we want to end the game
"Memory Closing" track (supplied by me) you to change "memory failure" to "memory closing", and add rain/thunder (this plays as the teams leave the game)

Plus the extra few screams/stabs as stand alone files

I've attached the Memory starting file (labelled Cabin - Opening v2.mp3) and Memory closing track (labelled Cabin - Closing.mp3) as a reference, I can supply other files when project is assigned.