Who should I add to my team to challenge the Elite 4? I have Kadabra, Suicine, Kolteon, Quilava. (Pokemon Crystal)

I have a level 40 Suicine, 43 Kadabra, 27 Jolteon, 35 Quilava in Pokemon Crystal.
I also have a 32 Poliwag, 32 Eevee, 36 Weepinbell, 20 Panphy.

I haven't yet gotten Lapras, but I did get a 15 Dratini. When researching how to defeat the Elite 4, I read that a dark Pokemon would be useful. Should I get Umbreon, and if so, is my level 32 Eevee too high level? I have a level 5 Eevee that I don't mind leveling. I've even read a walkthrough that recommended a Steelix, but that sentiment was not shared by anything else I read about Elite 4 team building.

I also read a lot of people suggesting Lapras. Is Lapras better than Suicine for the Elite 4?

I still haven't gotten to Victory Road, so I have plenty of time to level, and would be willing to catch low level Pokemon and raise them. I just don't know what I'm doing, as this is the first time I've played Pokemon since generation 1 was still popular...all those years ago. As a result, I'm not terribly familiar with new types like Dark and Steel.

Thanks in advance for any advice!

Do you need some advice how to build a powerful pokemon to defeat elite four? I can give you some advice..

I would very much appreciate that, Leia.

Ok, if you want to defeat the E4..you must have a pokemon that strong against their pokemon. I defeat them only with one Alakazam. You should teach your kadabra with this techniques and it will be almost invicible: ice punch, fire punch, thunder punch and pyschic. The first E4 member will use flying type pokemon at the beginning of the fight. Zapp~ the birdie using thunder punch. After that, he will use plant and another ice pokemon. Burn them up with fire punch..that finish them up, next will be a water pokemon so just zapp it up...after you win this battle, you will be fighting the second E4 member. He use poison type pokemon so use pyschic to them but watch out for the ball lookin' pokemon with thorny shell, its a plant type so use fire punch... Next would be a fighting type trainer..use flying or pyschic move to defeat them except for his onix, use water or ice move. After that you will be fighting a dark type trainer..first, she will use eevee dark evolution(i forgot its name), don't use kadabra unless its strong enough!! Use a fighting pokemon. Next she will be using gloom, just use fire or ice move. Next would be a birdie, Murkrow..zapp~ em up with thunder move..after that she use gengar or houndoom. Use Pyschic on gengar and water on Houndoom. Then finish, now you have to prepare for the dragon master..first he will use gyarados, just zapp~ em up like i said always..next would be a dragonite..use ice move ...after you defeat 3 or 2 dragonite, he will use his charizard or aerodactyol..just wash em up with water...and get ready for the final Dragonite..use ice move on them but it won't be a one - hit kill if you don't lvl up enough...after that prof.oak will congratulate you and your pokemon will be registered in the hall of fame...and one more thing.. You have to lvl up kadabra and suicune to lvl55 or lvl60 if you want to be safe..just VM me if you need help more..Arasoooooo~ i hope this guide will help you..

Thanks you, Leia. I will take your advice into consideration! I am leveling my team so far and they each at least level 44 now. I'll try to level them higher before I challenge the E4.

You should definitely add an Umbreon. Super effective against Ghost and Psychic types, which is REALLY helpful.

I ended up leveling my team to all be above level 50 before taking on the Elite 4, and I was able to defeat them very easily. None of the pokemon on my team fainted, and barely had to use any items. I guess I had overestimated the Elite 4 based on my memories of how difficult they were back in generation 1, Pokemon Blue. Thanks again for the advice.

Zorua, now that I have defeated the E4, I may raise one of my Eevees to be an Umbreon, just to explore dark type pokemon. Thank you for the suggestion.