1--In the options of the bone constrains, the drop only selects the armature, and the bone must be searched among the list of bones. No exist drop selector bone.
1-- create armature and add constraint in a bone / use drop for select a bone / object armature is select and not exist drop for select a bone

Not sure I understand correctly:

In this minimal example .blend I can select the armature and bone in the constraint:

Is this not working for you?
Please try to explain again what is missing for you or what the issue is (couldnt tell from the original report) and also provide an example .blend file along with it if neccessary.

2-- I also find that the multi selector "Alt" does not work on some options of bone constrains, for example the volume of strecht constraint ...
2-- select two bones and equal constraint configuration / press Alt and click in a button of constraint panel / has not change bones constraint property of all selected

Please dont mix multiple issues in a single report, please open up a new report for this...