I’m new to the forums, so glad to meet you all. I’ve been playing UMVC3 for about a year and a half but only somewhat recently I have actually become competitive.
Firebrand has been my favorite character from the very start and after a long time of experimenting I think I’ve found a very good team IMO that has somewhat underused partners that are overshadowed by the likes of Doom, Ammy, and Skrull. Here I will give a breakdown/guide of how this team is played.Feel free to leave any feedback, be it positive or even respectful criticism 
Point: Firebrand/Demon Missle (Charge)
Middle: Dante/Jam Session
Anchor: Frank West/Shopping Cart
Firebrand has some of the best mixups in the game thanks to his speed, air mobility and his infamous jumping L. Shopping Cart, when called out right, can allow Firebrand to rush in and provide nasty pressure with his instant overhead even when the opponent is advancing guard. The advancing guard can only be negated if you are plink dashing during your pressure with the Cart but wavedashing should be able to work to. Personally I just plink dash because that’s what I’m more used to doing. Jam Session can be used to limit enemy air mobility and allows Firebrand to approach from the air more safely himself. Shopping Cart is a better tool to apply intense ground pressure but Jam Session is the more capable assist when used against characters that tend to stay airborne a lot such as Magneto, Zero, etc.
In addition, there are two things a Firebrand team must have: an unblockable setup and a good hard tag combo due to weak solo damage. Jam Session is the perfect unblockable tool, keeping the enemy in hitsun long enough for Firebrand to hit with Demon Missle H (DMH) on incoming. However, Jam Session lasts a little less than Cold Star, Tenderizer, etc. so I’d reccomend putting Firebrand as close to the corner as possible when using an unblockable setup on incoming which will allow him to attack with the earliest possible hit of DMH
Now this is where the fun begins.
With this team setup, Frank West has the ability to go from Level 1 to Level 5 instantly after a hard tag from Firebrand once he uses Bon Voyage. Keep in mind though that hard tag combos into Frank West only work in midscreen or in a corner you are facing. My setup is:
Bon Voyage, hard tag into Frank, cr. L, cr. M, st. S, air L, air M x2, air H, air S, jump, qcf. H, cr. H, st. S, air H, air S, down H (immediately after air S), THC, mash during frank animation, snapshot x2
At this point some of you may have questions as to why Frank West is in anchor and not middle. If Frank was in middle, this team WOULD NOT WORK.
In order to achieve Level 5 with Frank, Dante must be his THC partner. This only works if Frank is in anchor position. There’s also another catch: using a THC with both Dante and Firebrand at the same time will drop the enemy out of the combo (Firebrand’s hyper carries them upwards) and prevent you from achieving Level 5 plus big damage. Because of this, when aiming for a Level 5 hard tag, keeping your meter at or under 1 bar when you start the combo with Firebrand is necessary to prevent Frank from building too much meter and causing a triple THC. However, hard tagging into Frank doesn’t work from everywhere on the screen. Snapping in another character after a basic Firebrand combo (ended with Bon Voyage to go to the corner), following up with an unblockable setup and then using Bon Voyage to initiate the hard tag will not only keep your meter in check (via snapback), but also guarantee you Level 5 Frank everytime.
On a brief note, Frank in the anchor spot provides good mixup oppurtunities for Dante, as Dante’s pressure game is subpar without an assist.
If you want to make sure you finish off the enemy with the hard tag combo, using X-Factor after the unblockable setup hits is not a bad idea, as once you obtain Level 5 with the X’d combo, Firebrand will do a lot more damage the next time he hard tags to Frank not because you’re in X-factor if theres still some of it left, but because of Frank’s increased strength. If X-factor is still present, the 2nd hard tag combo is a 100% kill. Plus, unblockable setups can be used when the enemy’s middle and anchor are incoming and while there’s a slight chance the setups will fail, the risk is still low so depleted x-factor won’t be an issue for you later on.
Now back to anchor Frank West. While it’s extrememly important to be in that position, even if he is in Level 5 his approach and ability to apply pressure leaves much to be desired. His only normal that hits low, cr. H, is slow, laggy and leaves the character wide open to be punished. However, Frank’s saws have great range, notably both his standing and jumping M, and are the perfect zoning tool for keeping foes out. Patience is key with Frank West if you want to get a solid hit off. Bait/frusterate the enemy into attacking with his saws, whiff kick and roll and once there’s an opening, strike.
Once this team gets started, its game over. Level 5 Frank, Firebrand and Dante? Too much to handle. Thanks for reading this guys and I hope this provides some inspiration for new Firebrand teams you may create in the future!