You were probably too hasty in deciding to repot in dead of winter, unless you live within 25* latitude of the equator, or so. Odds are high it's related to over-watering, but even if it isn't, I can't think of anything that would prompt me to repot in mid-winter because of some chlorotic leaves, which can occur from many different causes: diminished light in the plants recent past, over-watering, under-watering, over-fertilizing, under-fertilizing, soil compaction, root congestion, natural senescence, pH issues, toxicities, ..........

Not only that, but Fe (iron) deficiencies are often not due to an insufficient amount of Fe in the soil. As often as not, in containers, Fe deficiencies are caused by a pH issue. A pH above 6.0 for plants in pots makes acquisition of an adequate amount of Fe tough sledding. I get iron deficiencies in my plants over-wintering indoors every year; this, because of my 8.5+ pH tap water. The one step remedy is as easy as acidifying tap water with small amounts of white vinegar or citric acid (from stores that sell beer/wine making supplies), or using water from my R/O water purification system. The lower pH allows the iron to dissolve back into the soil solution.

Too, it sounds as though you're not at all sure it even was an Fe deficiency. In that case, it might have been better to flush the soil and start fertilizing with a fertilizer that includes all the nutrients essential to normal growth and in a ratio the plants would appreciate. My 'go-to' fertilizer for everything I grow is Foliage-Pro 9-3-6 by Dyna-Gro.

Al