1. How do you get seals for poke balls 2. How do you get the gym leader..

Sigh, you're new to Pokemon aren't you? I'll start with the evolutions.
Monferno evolves into Infernapeat Lv. 36
Kadabra evolves into Alakazam when traded to another game.
Unown do not evolve
Ponyta evolves into Raphidash at Lv. 40
Staravia evolves into Staraptor at Lv. 34
Psyduck evolves into Golduck at Lv. 33
Shellos evolves into Gastrodon at Lv. 30
Shinx evolves into Luxio at Lv. 15, who evolves into Luxray at Lv. 30
Bidoof evolves into Bibarel at Lv. 15
Onix evloves into Steelix when traded with a metal coat
Pachirishu does not evolve.

Alright, Your team is fairly weak, so ditch the Unown and set Ponyta asside since your Starter is already a Fire type. Add Bidoof for an HM slave, and Take Shinx and Psyduck and raise them along with your team to the 30s. You will not be able to get seals until you are at the 8th Gym. The location is at Sunyshore City. As for the 3rd Gym, it is a fighting type Gym. Use Kadabra and Staravia to tear the Gym apart. Once you reach the leader, Use Staravia on Meditite and Kadabra on Machoke. Use Monferno on Lucario and Kadabra and Staravia for backup.
The 4th Gym is the Pastoria Gym. They use Water types and your best bet is to get a grass type by then, since Crasher Wake (The Gym Leader) has a Quagsire. Use the Electric Pokemon I suggested on his Gyrados and Floatzel. If you were around Lv. 30 for the 3rd Gym, you should be fine.
The HeartHome Gym leader is the 5th one, so she will not appear until you first conquered Gym #3 and 4 first. The cute park, just take you Pachirisu in front of your party and walk around with it. It will pick up items and contest wear occasionly. No, the cute park has no connection with the gym.

Ok, I can answer a few of these but I don't remember all. 1. The seals for pokeballs can be bought at the Sunnyshore market which is a ways off for you because you can't get to sunnyshore till youve beaten all of the other seven gyms. I think you get the seal case in Solaceon.
2. The hearthome gym leader is actually the 5th badge. Shes in the contest hall at the top of the city. By the way, you can get into the cute Pokemon place by haveing a pikachu, a happiny, or another small cute pokemon. I don't remember any others but I'm sure theres a list somewhere.
3. The third gym leader is in Veilstone city, and uses fighting type pokemon. Your staravia will be really usefull but your kadabera and both your unowns will be almost totally useless. 4. I don't remember exacts on the evolutions of those Pokemon, but I can give you approxment levels.
psyduck-lv 33 evolves into golduck
shellos-lv 30 evolves into gastrodon.
shinx-lv 15 evolves into Luxio and lv 30 evolves into Luxray
bidoof-lv 15 evolves into bibarel
onix- evolves only when traded while it's holding a metal coat
pachirisu-doesnt evolve, but now I remember that it counts as a cute Pokemon that you can take into aminty square.
monferno-lv 36 evolves into Infernape
Kadabera evolves when traded
unown don't evolve
staravia evolves at 34 into staraptor
ponyta evolves at level 40 into rapidash
5. I think that you are probably going to need to stick to what youve got for the gym leader but I would switch out the unowns for something that isnt weak against fighting. The kadabera is also very disadvantaged against the fighting type but it is a high level. You might also want to switch it out, but I would only if you can replace it with something that is almost the same level.
6.the fourth gym leader is in Pastoria and uses water type pokemon. I suggest leveling up either the pachirisu or the shinx because they are both electric type and will be good against him. I personally prefer Pokemon that evolve, so I would level up the shinx because it has two evolutions. I found luxray to be very useful and I personally beileve that it is one of the best electric type Pokemon because it is one of the few you can get at the begining of the game that has a three stage evolution. I'm not sure what items to use but you should always have some super potions on hand. Something that completly heals your Pokemon is very useful.

Hope I helped