Thanks for reporting these in!
- Skills via Traits will be supported in Version 1.5.0 with the implementation of the Traits, States and Equipment feature. Use the standard Learn Skill and Forget Skill functions to manipulate deck contents for now. You can track what cards are in each Actor's deck by accessing the _skillCards variable of each Actor.
- Multiple Skill Types and Cards of different Skill Types will be supported in Version 1.4.0 with the implementation of the Card Types feature. To enforce Skill restrictions, you can keep track of the array of Skill IDs that are valid for each Actor/Class in a variable and then after any Skill is acquired run a Common Event that makes them forget the IDs of any Skills that are not in their valid Skills array.
- Cards can be selected via Mouse in battle by default, however, there is a bug in the Party Battle UI plugin that was brought up by another user. This is slated to be fixed in the upcoming Version 1.3.5 patch. We can certainly add in using Right Click to "cancel" out of selecting a card.
You can check on the delivery dates of these updates on our Trello. Hope some of these solutions help :)