The E answered most of your questions already.
Regarding 1): Directive tooltips are very easy to add. If you look at the event editor in FRED, there are two textboxes underneath the event list, these allow you to add a directive text to an event and a tooltip that disappears when the event turns true or false.
Regarding 2): Dialgue skips aren't very difficult to implement, but are a bit tedious. Basically, you want to 'unroll' the message list event into a bunch of individual message event, each of these being played if a) the first message in the chain has been played and b) the player hasn't pressed the skip dialogue key - I used the warp out key for that (
alt+J).
You need to reset your skip dialogue key at the beginning of a new list of message (using the
key-reset-multiple SEXP), and possibly tell the player that s/he can skip the dialogue via a training message.
Finally, you need to insert an '
or' logical condition in the event that is supposed to be played at the end of the message list, one of the or's cue being the original event's cue. The other cue is that both the first message has been played and that the skip dialogue key has been pressed.
If you want to see what this looks like, look at, for instance, mission 20, the event
M_Avatarr 1 to Moran 1 and each event chained to it and the
Activate Nav 1 event, then compare it to the original mission 20.
If you want an overview of the what else has been modified, have a look at the
TODO-list.ods spreadsheet, it should give you a list of generic modifications, modification ideas, per mission alterations and what dialogues are skippable, and possibly a bunch of silly comments

.
I've added dialogue skips to all but a few missions at the end of the game, and tested
most of those at least once (skips at the end of long missions are less likely to have been tested). So yeah, it would require a lot more testing before I'm confortable with making a "dialogue skip" release - nevermind the other stuff.