Regardless of the (intentional) mistranslation, I still think Chrom could have planned during the super early stages.
WARNING: STRAW GRASP APPROACHING
This early stage is when the Gematsu tipper obtained his info. Later on, roster is revised, and either Robin is added alongside Chrom, or replaces him outright. Rosalina is added here too. If Chrom wasn't cut at this point, he was probably one of the lowest priority characters. Chrom would later be cut due to not having enough time to fully create another unique character. Lucina is then promoted to fill his slot, leaving roster count intact. Chrom's model (one of the few things completed on him) was reused for Robin's Final Smash, which at the time, was undecided.
I will grasp as many straws as possible until Shulk happens