Only had chance to watch the first one but I think you're on the right track. My main pointer would be that if you are going to make it a more sound design based cue, with big hits, risers etc then the sounds you use need to be more unique and interesting.I think you're structure and ideas work though.
Wonderwoman is the best one, but then when the logo comes at the end you use some isntruments that sounds very MIDI and not at all epic.
The Transformers trailer is also quite good - especially the synths that join the arpeggio at 0:33 - they add a sense of "otherwordliness" to the piano which is kind of boring on its own. But then the strings that come on a few bars later are way too loud in the mix. There are a few such mixing issues throughout. Also, the bass that plays with the piano in the beginning sounds like a MIDI instrument. I bet it is - but I also bet you don't want it to sound like one.
The repeating piano note in the Alien one sounds too generic as well, you should "sound design" it a bit more. Overall I think the piano sounds in all of your songs that contain piano is kind of uninspired. Maybe use a transient shaper of compressor to work the attack a little, a little more high frequency "shine" on it and a wider stereo effect on the delay/reverb.
I didn't really like the guitar sound in the Justice League trailer.
You're good but there's room for improvement. There are some mixing problems and some instruments that I think sound kind of uninspired or off.
Good job on these. I think it's a great idea to go through the process, see what's needed, then once you've finished and gotten away from it for a bit, go back and compare it to the original soundtrack. You'll probably find theres a bit more dialog and sfx, and a bit more percussion, but I'm glad these versions showcase your music. More of that is good.
The only suggestion I would make is changing the music out a bit more in justice league. Either introduct the guitar piece, cut to a different track with drive (perhaps heavy percussion piece) then cut back to the guitar for the end, OR build on the guitar track after it starts so it gets bigger (adding percussion or orchestal stings or brass) so by the end it's a more massive thing. I think because it's fairly consistent enrgy-wise through most of the trailer it's less impactful. But that's not too difficult of a fix. Congrats on the solid work, I look forward to seeing more.
I use my synth piano and a software called Magix Music Maker and its VST (i know it's not very pro, but i dont have possibility to have better), and some other softwares and freewares to create and record a lot of sounds, instruments and samples.
I work a lot on sounds with some transformations to create something harmonious.
In this case, the drums are a mix of some percussions, electro and real.