You might want to use
https://coinb.in/ to script your raw transaction. If you were to include any of the inputs from the first transaction (de188ec7...) in your new transaction, then that transaction and its descendants will also be invalidated when it gets confirmed and you should be able to make the other transactions as well.
That sounds promising. I have never scripted a raw transaction before and am a bit puzzled what exactly to put into the the fields at
https://coinb.in/.
Would you (or anyone) be able to assist me with this as I do not want to make any errors. Feeling bad enough already that I created this mess in the first place.