Norway maple can have the trunk split open during cold weather in an exposed position and cold climate. The locust also sounds like it froze down. Otherwise, when sections of top die on trees and shrubs there is either a problem with the root area, such as impeded drainage or pathogenic infestations (honey fungus, water molds...) or they are being drilled out by boring insects - the latter is probably not the case here. It sounds like both trees should be replaced with different choices.

I'm interested in you tree for hosta..

Hi Iscarus , Where are you located please? I am interested but kind of depends on where you are . Signet

Anything over about 2" diameter at the base will be very difficult to transplant without a mechanical tree spade. And don't even try until fall. Also, you cannot keep a Norway maple small by trimming it without ruining it and weakening it (as in "topping" it). And that is probably what the power company will do to it. And, as you know from the bigger ones nearby, Norways have heavy shade.I'd say your options are limited.