Story Ideas Help

Sure. It will be a pleasure to help you out. I think that focusing on a small campaign will make completing the story easier. That way the group doesn't get stuck, bogged down or burnout from a single campaign. Characters can come back for the next campaign and any relationships forged will continue to foster. It would be better finish a shorter campaign or two then remain on a single larger one and not finish it.

What kind of players will be in this campaign? Both the people playing and their characters. Perhaps some details on the Infinity characters and their backstory could be used to help shape this campaign you are coming up with.
Is it alright to ask if there is any more room in the party for another player? I might want to join depending on the group and campaign setting.

Out of the 5 backdrops you mentioned above I'd go with the Mayacast Personality with the Terrorist connection. It sounds the most interest of the 5 to me.

As for campaign backdrops I got a few ideas:

1. The nation of Haqqislam is presented pleasingly on a brightly colored canvas. But very dark things are hidden underneath these colorful layers.
When a rich Corporate hears that his/her child and their spouse died on a family trip to Bourak and their surviving grandchild/children are now wards of the Haqqite state he/she hires a group to track them down and bring them home safely. But when the players reach Bourak they find themselves being stonewalled at every turn. What's worse is the grandchild/children have suddenly disappeared from the state's Al-Mustaslaha (Orphaned, Donated, Delivered) records. Urged to continue the search by their client the group begins to unravel a dark secret lurking behind the institution. One that appears to have it's tendrils deep in the system. Siphoning children & teens never to be recovered.
Who or what is behind this? It doesn't matter who or what it is. What matters is bringing the child/children back home safe & sound. Leave no child behind.

2. One would think that the art of farming genetically adapting crops that are hardier to disease & produce more bountiful harvests is something that most people wouldn't have a problem with. The eco-terrorists of Eco-Aktion are not most people. They are extremely zealous of keeping the what they refer to as the "evolutionary genetic pools" pure with no alterations. Wanting evolution to change specimens not Mankind. They use tailored viral & genetic weapons, bombings along with sabotage to accomplish this goal. Wether it's terra-forming, hybridization of crops or creatures, simply introducing new species into an environment or removing a species from an environment this group born on the planet Acontecimento are against it all.

Farming on Acontecimento has been a violent topic. From radical Camoen farmers who try to violate the Selva Preta Reserve to open up new farmland to grow crops in. The constant farmland claim skirmishes between clan farmers in Orujo & La Guardia's conjoined zones. Eco-terrorists bombing targets in Bharata & Cidade BomJesus. While also threatening resort owners who wish to build near natural phenomena to draw in customers. Then there is Aleph's experimental automated farms in Adarsana which is facing stiff opposition from both clan farmers & CFZ Corporations. The subject has been anything but a peaceful one.

Zacuto is a sleepy conservative town on the continent of BomJesus. This continent is home to one of the greatest population centers of the Church in the Human Sphere. The town is the hub for the Zacuto Continental Farming Zone and has recently taken part in a test drive for an experimental crop to see how it fares. However this action has riled up a nearby Eco Envoy of Eco-Aktion. Who after creating mission parameters & coordinating larger campaign actions sent for an Eco-Aktion RAG (Research Action Group). It was then that trouble started for the farmers. The eco-terrorists began their campaign of destruction of the hybrid crops but then the violence escalated and the farmers were being targeted as well. It seemed that whoever was leading this RAG had a personal bone to pick with the Christian population and was using Eco-Aktion as a means to carry out their personal vendetta.

Viewing this as a hate crime the Church hired a group of Mercs to be lead by a Father Knight & a contingent of knights. The goal being to bring righteous retaliation upon the terrorists in the form of gunfire. Help the farmers in their current predicament and save their livelihood. Shatter the eco-terrorists & break them to pieces.

3. Equinox, a former Praxis Lab that turned shadow collective after a violent campaign from the Hassasins, are cells of paranoid mad scientists & engineers to put it plainly. Their research, experiments & discovered goals have made them a danger to the Human Sphere as well as themselves. Due to the convert natures of their cells contact agents are used to procure raw materials to fuel their insidious works. These agents also find job opportunities for Equinox members to work as Mercenaries to those who are desperate or enterprising enough to accept their services.

So why then has one of these contact agents been approaching Mercs with a job offer instead of the other way around?
It turns out that a certain Equinox cell has been ransacked & destroyed with only a few survivors remaining. The culprits of this act according to a survivor were part of the Yu Jingese military being lead by an Imperial Service Agent. They swooped in and took all the research they could grab while killing any Equinox members that they came across. Interestingly the Yu Jingese were tracked back to an asteroid in the Human Edge that served as a cover for a secret base.

Questions about how did the Imperial Secret Service found the hidden cell in the first place will have to be put on the back burner. The survivors want revenge and are worried about what the Jade Giant would do with their notes & specimens. The players are hired to return the favor. Smash and grab the data or if that is not possible simply destroy it. It is better that no one gets their hands on the research if Equinox are unable to repossess their hard work.