If you have a specific version of an application that you want to keep, and not replace with a newer version from the Play store, you can create your own apk file using ES File Explorer (an application that everyone should have anyway). In addition to being able to view the files on your phone, ES File Explorer has an "Application" button. Select it, and it will list all of your installed applications. Long press on any application, select "Backup", and it will create an apk on your phone. Location: /sd/backup/apps. Now you have an apk you can use to side load the application to another android device, and you can store on the cloud if you wish. This is a pretty convenient solution to your described situation as I am understanding it, and not very time consuming or complicated.
Reinstalling things like RSA software does require that you have your original information provided by your IT Team. If you saved you corporate e-mail with the instructions, you shoud have everything you need to get it back up and running. It's simply a matter of reinstalling the software, then opening a special seed file that you were provided with initially (usually via link). If you don't have it, you can always ask for it -- even if you AREN'T going to reset your phone, if you don't have this information, you should get it because your phone could become lost, broken, or you may have technical problems that FORCE you to factory reset. By being proactive, you have this information, whether or not you intend to factory reset after the LP upgrade or any other time.
If you use Apex or Nova as an alternative Launcher, you can back up your desktop and page layouts, so they can be restored after a factory reset, fairly painlessly.
Getting all of your mail accounts playing nice with each other is a whole 'nuther story. Yeah, that can be pain in the arse, and not only that, but setting it up again from scratch in LP may be an even bigger headache than when you did it in KK (or easier -- but I doubt it).
This isn't a post trying to twist your arm into "joining" those of us who always factory reset after a major OS update, but I did want you to know you have options, and that some of the road blocks may not be as difficult to surmount as you initially think. Planning in advance helps too <wink!>.