Hi Alyssa, I'm a local PM and Broker and have spent much time in these area and know them well. I thought I'd add my two cents:
46219 - The crown jewel of this zip code is Irvington which is where Butler University was founded prior to moving further North. Irvington is a really cool and unique community. The South end of Irvington near Brookville road is not a nice as the other areas of this community. The Little Flower neighborhood is located just North of Irvington and is also a historic neighborhood that has seen some attention. Next in line is Community Heights which is pretty inconsistent. I implore you to look very carefully at specific streets as these neighborhoods are very inconsistent.
46203 - This encompasses a lot of areas. As you may be aware already, the best of this area is Fountain Square, Fletcher place, Garfield Park and Bean Creek. GF & BC are definitely areas that have seen growth. FS & FP are trendy/expensive downtown markets now.
I love the fact that you've decided to make the trip out. It will provide you soo much value to just drive around these areas and get to know them better.
If you have any other questions or want to chat - feel free to fire over a DM my way.
Best of luck and happy hunting!