Sims 3 Origin base game version 1.69.43.024017 question

Hello and thank you for such an amazingly resourceful, helpful and polite forum!  

I have spent the last approx eight hours searching through posts and reading every possible thing available on here to find the answer to my questions, but I could not find them so I thought I would ask.  My sincere apologies if this is obvious information which I have overlooked.  Also my apologies if this post in the wrong place!  I thought a long time about where it was appropriate and in the end I just put it here.  

I own the base game (version 1.69.43.024017) a few EPs which I play through Origin.

I have two questions:

Can I install the G4TW EPs that I want and still use the base version of the game that I have been playing through Origin?

I see the instructions and a lot of users posts saying this is possible, but my worry is that the base version of my game is too high to be able to let the patcher do its thing and it won't work and then I will have to uninstall and reinstall the entire game and possibly lose information on games I already own through Origin.

My second question is:  I am wondering if it would be beneficial to just entirely uninstall the game I play through Origin, get Origin and The Sims 3 both entirely off my machine, and then re-install everything using only G4TW files and not Origin at all.

I have all of the CD keys for the ones I own, except for WA because I just bought it recently and for some reason EA doesn't list my CD key in Origin anymore?? 

Essentially what I want to do is have ALL of the Sims 3 and I believe I am in the right place to do that.  My worry is that if it doesn't work on this machine properly for whatever reason that I could go back to the Origin set-up that I have now without having to repurchase anything.

I hope that all makes sense.  If you read this far, you are awesome and I hope you have a great night of Simming!

Just an update to my own thread.  I did some more reading and after reading this thread and being that I use a lot of NRAAS mods, I am going to follow the directions in this thread and just reinstall an entirely new copy of the Sims 3 fresh from G4TW.  Wish me luck, with all of the resources on this site I may not even be back with more questions!

Have a very Merry Christmas!

Hello, and thank you so much!    It's all installed now and working perfectly!  If I run into any issues I'll be back.  I'm so happy that I now have 6 EPs I never had before.  Hurray!