mobile

Hello everyone, please be patient with me as I am relatively new to modifying phones. However, I have spent a good portion of the past 1-2 weeks looking into this problem on XDA + google, and I am at the end of my rope.
Here is my problem (I'm sure you already know):
I have no current solution to installing a custom recovery on my phone. I really just want custom recovery to restore FULL backups via Nandroid or equivalent.
Here are my questions:
1) In download mode, Odin has no problem flashing an official image/firmware (tar.md5) to the phone. Is it possible to create my own image of my phone into one file and flash it via Odin to my phone when I would like to restore? I have a feeling that something in the phone checks the hash of the image (I'm sure that I'm not saying it right), and that, considering my image would be twice the size of the official, there would be no way to make my image pass using collisions or what not. However, this would probably be my first choice after safestrap (assuming that won't work), so let me know.
2) I have read that certain people with phones similar to mine (not my variant though) have successfully "swapped" the external and internal SD cards. If I remember correctly they just change a couple lines in void.fstab. If this could actually be done, I could easily restore a backup to the now external internal SD, then change the settings to reswap on reboot. I feel like this is too good to be true though, as I have not seen this as a solution to my specific problem online. Is this actually a suitable option?
3) Currently my phone model is not an officially recognized device which Safestrap will work on. However, I have read that it is possible to do on my model using the Safestrap version which corresponds to a close variant of my phone. Can this be done? Please let me know if you have any information on this.
4) I guess this would be the last resort. I'm pretty good at taking things apart, but even better I can put those things back together :) Is the internal "SD" really just an SD card deep inside the phone? Would it be possible to replace that card for the purpose of backing up?
Here are my phone specs:
-Samsung Galaxy S4 Mini (SCH-I435)
-The carrier is Verizon Wireless
-Android Version 4.4.2 (kitkat)
-Baseband Version I435VRUBOC1
-Kernel Version 3.4.0 dpi@SWDD3013 #1 Fri May 23 2014
-Build Number KOT49H.I435VRUBOC1
-Hardware Version I435.05
-Configuration version B13.SAM.SCHI435.0
-Needless to say, phone is rooted and has busybox + etc correctly installed.

Any help will be greatly, GREATLY appreciated -- even if that help is telling me that it isn't possible. I can't seem to give up on this.
Thanks,
Kurt