Yes for the most part, most things you mentioned could be done with action parts & the editor systems alone, but scripting would be much faster & easier.
1. delete all animations in characters that aren't facing left or right (the entire animation, not just the animation frames) & the engine will auto-default to the next nearest animation direction while the game is running.
2. yes it's possible. vs has 2 built in systems for keyboard handling which is key actions & a scripting solution which uses an event handler to listen out for key presses/holds/releases, etc. I believe a tiny bit of scripting would be needed for this, but Simon wrote a script a while back which allows you to control your character with the keyboard or a gamepad - all you need to do is create a new script in the script section of the editor & paste the script in (not sure where the script is right now)
3a. yes, you can move npc, objects, & animations. there are action parts that allow you to move characters & objects - animations attached to objects would move if the object is moved, or you can move animations instead. If you want to include easing in the movement, then Lua script is required, but it's very easy as it's only a single line of code to move something.
3b. not sure what you mean here - I'm still half asleep. Quick note: parallax scrolling is possible in VS (no scripting required).
4. not without scripting, but there is a script example available on the wiki, that's more or less plug & play, same as the gamepad/keyboard movement script. You might need to edit the offset values a bit, but just so you know, characters can't really talk & walk at the same time, though you could use trickery by setting the display text as a background text & changing to an outfit where a talk animation is included in the walk animation of the character - there are other solutions/workarounds too (always so many different workarounds when it comes to Visionaire).
5. As I already said, yes for the most part, but take in mind that Visionaire Studio is a point & click game engine that was designed with point & click games in mind - though Simon is working on making it much more flexible with each update for creating other game genres with the engine (box2d physics, instancing, & a visual scripting system are in the works), which will make it easier to create other genres, such as platformers for example.
If you want a straight up out of the box engine that was geared for the creation of side-scrollers, then it might be worth looking into gamemaker studio 2, as it also allows you to create games with their own version of action parts (premade actions/events/queries) or via script. It's a great engine, but it is somewhat pricey & complicated if you want to release your game on anything other than windows.
P.S: feel free to join our Discord server
if you have any more questions - me & Simon are online there most of the time. We are in the EU, but are online until late most days.