Most dogs would do fine with a little bit of ice cream.
It is the amount given and the particular dog's sensitivity to certain foods that would be the question.
Some dogs can't really tolerate any dairy, so it would be out for them.
I also wouldn't recommend feeding it to dogs with pancreatitis issues unless you are sure they can handle it.
While I would not recommend that anyone feed their dog any type of artificial sweetener, the ASPCA does not believe that Splenda causes any serious side effects this far (except maybe GI upset). Xylitol is the worst. If your dog gets a couple of bites of something with Splenda, they should be just fine, but I would not recommend intentionally feeding it.
ASPCA Blog: Pet Poison Q & A: Sweet Talk