I just went back to a 95' YJ 4.0L. I had a Rio Grande as my first SWB jeep and ran it almost to 190k with stock everything but 31's and few bolt ons. Sometimes not having enough power, Can get you into trouble just the same as lacking to get ya into it.
They both have their place and seems you have already don't the homework that a 4cyl is a town jeep for the most part in terms of power/speed. Of all the first vehicles, You picked a perfect first for you're daughter. Box frame, Stock cage etc just in case of *** hats, She will be safe.
If the tires are new and the jeep looks good, Just re-gear the axles to 4.88's. Will still keep speeds down but will look better and mpg will be the same for in town. That's how much it will cost to drop the BL and what not and find/trade/buy 31's.
To each their own, Another vote for kickass dad! Good luck on the project