The divine to breed with Cancer to get Leo will be Gemini but not sure if it is either one, must have both or a specific one ( dark or light)

try for Cancer in the HOPs throughout the promo. During the Festivities (lottery) portion of the promo, anyone who opens a certain amount of HoPs will have Cancer pop up in their reserved sales.

The cost of 15-20 passes in the reserved sales is just an estimation based on a post in the International Horse's spoiler topic that said it would cost no more than 35 passes tops for Cancer.

The Plant promo is next correct?

way to get passes for equus?

There's a bar on the pass page that fills up, up to 300 points. Once you have reached 300 points you can buy the pass. The pass page just says the bar is updated every day, based on the actions you do on the game, but there's no detailed info what actions affect it and how.

what kinds of actions must be done to fill up the meter?

is free

It appears your seniority and actions are the two main components but beyond that we have no further information. It could be just those two or others as well.

Le Pass de l'Assidu

Obtenez un pass gratuitement en jouant !

Le pass de l'assidu vous permet de gagner des pass en jouant à Equideow. Vous êtes ainsi récompensé pour participer activement à la vie du jeu.

Fonctionnement

Sur la page des pass,vous pouvez découvrir la jauge du pass de l'assidu. Cette jauge augmente en fonction de vos actions sur le jeu de 10 points par jour au maximum, jusqu'à un total de 300 points. En jouant normalement, vous verrez cette jauge grimper progressivement.

Une fois la jauge complétée, allez sur la page des pass et jouez à un mini-jeu. Vous recevez le pass lorsque vous réussissez le mini-jeu. Si vous échouez au mini-jeu, vous pouvez recommencer autant de fois que nécessaire.

Important : la jauge n'apparait que sur un seul monde. Par défaut, elle a été activée sur le monde où vous vous êtes inscrit en premier. Vous pouvez la changer de monde comme vous le souhaitez. Dans ce cas, la jauge est réinitialisée.

Les actions prises en compte sont celles que vous effectuez sur le monde où la jauge est active.
Conditions d'accès

avoir validé son adresse email (rendez-vous sur la page mon compte si ce n'est pas le cas)
Avoir au moins 30 jours d'ancienneté

Astuces

Si vous ne vous connectez pas ou ne faites pas d'actions sur le jeu, votre jauge ne bougera pas.
En faisant grimper votre jauge de 10 points par jour, vous obtiendrez votre pass au bout de 30 jours.
Si vous ne faites pas suffisamment d'actions pour obtenir 10 points/jour vous pouvez en obtenir moins. Par exemple 3 points au premier jour, 9 points au deuxième jour vous feront donc 12 points au total.
La co-gestion ne permet pas de faire monter la jauge.
Les actions qui font grimper la jauge sont maintenues secrètes.

They talk about some sort of mini-game so whoever translates it could help with that part ??

Pass the Assidu

Get a free pass while playing!

The pass of the Patient lets you earn playing Equideow pass. You are rewarded for actively participating in the life of the game.

Operation

On the page of the pass, you can discover the gauge of the hard pass. This gauge increases depending on your actions on the game of 10 points per day at most, to a total of 300 points. Playing normally, you will see this gauge climb gradually.

Once completed the gauge, go to the page of the past and playing a mini-game. You receive the pass when you pass the mini-game. If you fail the mini-game, you can repeat as many times as necessary.

Important: the gauge only appears on one world. By default, it is enabled on the world where you registered first. You can change the world as you wish. In this case, the gauge is reset.

Actions taken into account are those you make on the world where the gauge is active.
Terms of Access

have validated their email address (please visit your account page if it is not)
Have at least 30 days of seniority

tips

If you do not log or do not share about the game, your gauge will not move.
By driving up your gauge of 10 points per day, you will get your pass after 30 days.
If you do not obtain enough shares to 10 points / day you can get less. For example 3 points the first day, 9 points to the second day will make you so 12 points in total.
Co-management does not raise the gauge.
The actions that drive up the gauge are kept secret.

It sounds like you are only going to be able to get a pass on one server...well actually no. That probably means you will be able to get a pass on every server, but since the French server has Gaia and Ouranous worlds, you will only be able to get a pass on one of those worlds, not both.