From the Making of Fire Emblem: 25 Years of Development Secrets book comes a small snippet on page 81 regarding how Chrom’s design was meant to resemble Ike’s (with a bit of Marth).
You can find much more from this book on the compilation post here.
As you can imagine, the process of doing all this (scanning, editing, translating in some cases, etc) took a lot of time, and I am unemployed… so if you like what I did, then please donate! (the button can be found in the top right of the page)
Enjoy!