Starting from 1:07 I feel you would be better off attempting to walk towards Mario and closing the distance.
Mario could afford to approach you with b-air, his airspeed is amazing as you probably know so jumping as Luigi can be a real commitment that you will regret. It will also give Mario enough time to think about what he would like to do next as we take a fair amount of time to land from a full hop, so it's not a situation you want force yourself into often without having to.
2:15 best d-throw set up you could have done in that situation imo so good decision making, the only thing again I would suggest is walk. I think you would have punished Smasher's shield if you have not dashed past him, I'm not telling you to walk literally everywhere but you will have access to perfect shielding (for projectiles and making your way in it's huge) and it's not such a commitment for you to have to stop momentum.
2:29 - Bad fireball spacing and choice, it's a problem that all Luigi players have gotten punished for, grounded fireballs are mostly for mid-screen poking which gives us time to make our way in. If the opponent gives the fireball TOO MUCH respect then that is when we can begin play around with player habits. In reality the reason why fireball use has to be on point is because the hitstun on a fireball grounded is minimal, the opponent can hit their fastest button and pretty much negate the hitstun. Fortunate for us, as long as we are spaced correctly we still have one of the best jabs in the game so we can play with that when the situation arises.
2:35 - Hyper you did exactly what I was mentioning earlier and made your way through so much easier so from here it looks like you have already adapted.
Woah... A little after you start rolling a lot, as if it's a comfort zone to movement... In time if this happen is not under control it will cost you games.
2:57 - I can't tell if you want that or a reverse fireball but if that had been misfire would have been the game
I would have laughed and been happy for you.
3:22 - Okay this point I will make is probably the most important so far, I also suffer with this problem at times. Hyper, you gave up so much space and let him come back to stage for free. I really do not think you had to move right so much, I think if you had stayed put you would have kept center stage and given smasher more to worry about but...I can see why you did move as you were probably feeling cautious or at least that is what I think you are thinking at this point.
Good finish to 1st game.
4:48 - Any Luigi who reads this, please try to avoid using u-tilt before 27-29%(roughly) you are basically about to be punished ON HIT and give up your pressure.
Decent use of tilts, you probably use tilts more than I do I prefer use jab because it's quicker and for stage positioning of myself and the opponent. Though you are not being punished as yet and it's decent damage and in this mu as long as Mario not SH'ing it's definitely good use.
5:13- Ahh damn, that was a shield grab opportunity I felt that was a early kill possibility... Gotta make people feel bad for attacking your shield without spacing but this is for future. Playing and watching/critiquing are very different so I hope I don't sound like I am trying to demean you or anything.
5:15 - The jump was a evasion to the fair so I can respect that, the only thing I can suggest is DI first, the jump may have come a little too quick but if there really is no other choice then yeah you gotta do what you gotta do but that was a rough situation to be in landing was always difficult once you had used your jump.
5:41 - For future scenarios like this, jump cyclone catch an air-dodge and kill an opponent
I really feel you could have done that, try for yourself against friends/rivals in casual sessions and see if you feel comfortable but I've done it enough to know. U-air was not a wrong choice though, good damage and juggling it's just when you are down taking the stock is what you need but this is just for future cases. Playing the situation safe in a tournament setting is what I usually do but when times are looking grim is when you are forced to start taking risks that are worth the reward.
6:48 - Gotta walk, perfect shield and intimidate smasher. As the commentator said you were losing the neutral fireballs war because Mario can play it better than we can. It's why just dashing all the time is ill-advised, walking is slower but we still have all our options on deck when we want them.
LOL damn Game 3 not much to say or suggest you did your thing