I know you will be able to be the best low tier main in Dallas/Houston.
My favorite counterpick are Brinstar, Norfair(when legal), Frigate, and Castle Siege. But they are not the best against some characters.
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MK
For MK, I prefer fighting him in neutral stages, like Final D or Smashville for the first match. My cp for him are FD, Yoshi Island, and/or Pokemon Stadium.
FD- lets Falcon have more ground mobility than mk and he can abuse grab releases; however, it will allow metaknight to punish landing easier.
Yoshi- Will cut his aerial mobility by a lot and it gives Falcon more ground mobility; however, it will also cut or aerial mobility.
Pokemon Stadium- is like FD, however some of the transformation allow Falcon to infinite MK or at least does a lot damage with F-throw, Jabs, and F-tilt into a wall. The part of the stage that will hurt falcon a lot is when the windmill shows up. Stay away from the windmill when facing characters with disjoint.
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ZERO SUIT SAMUS
Her style is similar to Falcon. So I will prefer fighting her in Smashville or Yoshi for the First match. My cp are Yoshi, Frigate, Battlefield.
Yoshi- It cuts her aerial mobility and we have more ground mobility in this stage than her. But we will also lose aerial mobility.
Frigate- Will reduce her recovery potential in one of the transformation. But it will also force us to recover into stage. 2nd transformation cuts down aerial mobility, but the slope will help zss samus more.
Battlefield- Gives ZSS a lot of platform pressure, but we can also give that pressure. If she or we fall out of the platform is a free d-smash or jab/ tilt lock.
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SONIC
I don't have sonic experience
my only advice is avoid picto or yoshi against sonic. I will try Brinstar against him, but I don't have experience in the matchup.
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WARIO
My favorite matchup
I like playing him in the first stage in FD, Smashville, Yoshi. My CP are FD, Picto(if legal), Smashville.
(Grab release- Knee, Spike, UpB, D-smash, F-smash(tilted), Up-smash(but can be sdi) Uptilt, Upair, F-tilt, grab)
FD- We have stage control, grab release for the kill, and grab releases for building damage. Our up air will beat most of his aerial if space, Jab can be use as an anti air some situations. Our speed allows us to take advantage.
Picto- same than FD, but transformation may hinder grab releases and help wario; however, it can also help Falcon allowing him to use wall techniques. It also helps you not to get fart when recovering.
Smashville- Like FD but the platform may hinder killing grab releases, but we can still grab release to up b with the platform.
Yoshi- Limits his aerial mobility but it reduces our grab release; however, we can do grab release to up b. If we grab him in the corner or when the platform is going up we can do our killing grab releases.
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MARTH
This another matchup that I like playing. First stage to will be FD, Smashville. My cps are FD, Brinstar, Smashville.
FD- Makes Marth upb easier to punish. If you bait the up b is a 50% kill with Falcon Punch. So stop the Marth player from using upb to break jab combos. FD also limits his aerial pressure and a big stage give us mobility to fight him. With the space we can bait easier. Side b can be sdi into a grab or jab.
Smashville- Is the most neutral stage for this matchup. Both character benefit from it. But the platform helps him more.
Brinstar- This stage can be a good counterpick or a horrible one. In theory this stage helps marth a lot, but If you know the stage you can see that Falcon gains more benefit from this stage than marth. Platform help marth in his pressure but the lava and the shape of the stage stops most of the pressure.
However, if the marth player knows this stage, it will be a hard battle. We have good gimmicks in this stage. ( I might be biased toward this stage)
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ICE CLIMBERS
I don't have that much experience. But what I can tell you from my matches against some Ice Climbers is that stages with platform will help our mobility and that they hate stages like brinstar, RC, Norfair.
This is one of the matchup I will hate playing it in Yoshis. lol It cuts or aerial mobility and the platforms get us up air by the Ice climbers. FD is a no no. Try to take this fight into the ledge and always stay moving. Our speed allows not to get grab; however, most of our moves are not safe on shield. If we can get a side b punish we can get them in the air and kill nana. If you grab them f-throw them.
Cps Smashville, Brinstar, RC. Battlefield can be good, but the Iceclimber upair does so much damage and gives a lot of pressure.
SORRY FOR THE WALL OF TEXT, I wish I could use HTML tags so I can format the text better.