Well, i've had my writer's block moments against some of those characters and I can only provide very general solutions that have helped me immensely.
First of all, like what gallax crossovers are good for f-air approaching.
Against G&W, I normally refrain from t-jolts (maybe risk 1, but DONT after 1 t-jolt has been captured). I would bait b-air from g&W. If it was baited high, just run in u-air or something and get the juggles ^_^. If b-air was baited low, try to full hop over it before it reaches you and tag his landing or do a t-jolt (if spacings right, its always a free and bucket-safe t-jolt if GW recklessly b-airs). Once GW has a full bucket, I work on spacing away from it (No.1 priority), baiting it out (if i have high damage anyways--beats getting 0% KO'ed later), or letting my thunders and jolts fly (after trying the first 2 options).
Falco's... crawling is only ever helpful for me in this matchup. Other than that, lasers should be AS much of a problem if you mix full hops, short hops, and double hop approaches. If you approach in a mix of these ways, there should be spacing opportunities if the falco guesses the wrong height you tried to jump. QaC approaching over the lasers (or under them if falco jumps higher) is enough to throw off most falco's laser consistency. Once that happens, you can now approach and space medium distance wise cuz the falco may start anticipating QaC shenanigans (he'll probably start jab cancelling, n-airing or stuff). Spacing is the REAL factor in determining what works or not. Fiddle around with various horizontal (walking, powershielding, running, QaC'ing, airdodging) as well as vertical (Shorthop, full hop, double jump, sh>doublejump) spacings and you'll find a couple that will eventually work (falco's lasers and reflecters and stupid jabs or illusion can't be in all those places at once ^_^).
Lucas's, I'd powershield pk fires, fully shield throw d-airs and n-airs with maybe a spotdodge midway through their moves and rinse and repeat with lots of jumps and airdodges inbetween to get closer to em. I find that t-jolts REALLY KILL and are absorb safe IF AND ONLY IF lucas NEEDS the vertical component of his second jump for spacing (cuz maybe lucas's recovery/up-b will get gimped otherwise). T-jolt them in this scenario and they'll get gimped if they absorb it or take it and possibly get combo'd or another kind of gimp instead. Otherwise, I usually refrain from t-jolting too much. For me, at least with n-air, if you read it right, a hyphen u-smash will kill a lucas if they short hop nair. U-air also works with tight spacing of your u-air. If you get lucas in a grab and he's decently high in damage (or your opponent has a history of temper problems) you could mix up 50/50 grab release mindgames (which is demoralizing for the Mama's Boys). If you do most of your stuff with a little bit of retreating and baiting, opportunities should present themselves if you start reacting to their moves more closely. And as for pika and approaching, pika has the speed and a couple of moves that make him POTENTIALLY a really good rusher, but it still requires a lot of patience, reading, and a bit of luck sometimes to really approach continuously (as opposed to some MK's that can rush 24/7 without any problems).
As for olimars, its just plain reading them. The matchup is stupidly hard if you just think of it in terms of t-jolt (it won't work....). Pretty much, I just rush in and hope for the best (f-smash or grab? spotdodge or powershield... Shield, roll or pivot grab? Grab, dash-dance pivot grabs, or jump>t-jolt....). Just play the matchup more and you should get a feel for it.
If there are not any platforms, try t-jolting the ice-blocker's head and both the IC's rarely powershield at the same time so it may throw off their sync/desync. Technically, you don't have to approach in this matchup--just wait for them to come to you. Likewise, you could just walk and d-tilt or f-tilt the first iceblock and the second one should rebound back towards IC's. Try moving them towards the edge so they'll have less room to move back and pivot grab. Also you could fake a t-jolt attempt and do a QaC retreat or approach if the spacing is right instead and see how the IC's respond. What you can do is trade a missed pivot grab with t-jolts and retreat aerially if ice blocks cancelled full hop t-jolts. Otherwise, much like against Olimar, get used to spacing for opportunities whenever you find them when playing the matchup more.