If you want a sport horse, then the taller colt is the only option here. He has a much better rear end and will probably be able to jump, at least small jumps and maybe a lot more than that.
Heads on both will be acceptable, but not gorgeous. Freisans aren't noted for pretty heads.
Neither one of those colts is stallion quality, I don't care what country you are in.
I've driven a lot of horses and I've owned half a dozen stallions and there is no way, under any circumstances, that I would use a stallion as a driving horse anywhere else except inside a riding arena with trained handlers standing by. You must be able to trust a driving horse 99.9% every second that you have them in harness. Even the very best behaved stallions, I would never trust more than 30%, and I have owned and been around some very steady good-natured stallions---- all of them pure western cattle horse breeding or draft horse, and not ever one with any sort of hot blood.
A few seconds of silliness with a saddle horse and you can usually go with them and get them under control again. A few seconds of silliness in harness can result in broken equipment, severely injured drivers, injured bystanders, broken legs, and shafts through the horse's belly. Don't do it.