These are all the statistics on the Elite Four for versions Red, Blue,and Yellow.
#1: LORELEI
POKEMON:
DEWGONG LV: 54
CLOYSTER LV: 53
SLOWBRO LV: 54
JYNX LV: 56
LAPRAS LV: 56
RECOMMENDATIONS: PIKACHU LV: 60 OR HIGHER
#2: BRUNO
POKEMON:
ONIX LV: 53
HITMONCHAN LV: 55
HITMONLEE LV: 55
ONIX LV: 56
MACHAMP LV: 58
RECOMMENDATIONS: ALAKAZAM LV: 65 OR HIGHER
#3: AGATHA
POKEMON:
GENGAR LV: 56
GOLBAT LV: 56
HAUNTER LV: 55
ARBOK LV: 58
GENGAR LV: 60
RECOMMENDATIONS: ANY POKEMON THAT KNOWS DIG AND THAT ARE ON LV: 70 OR HIGHER
#4: LANCE
POKEMON:
GYARADOS LV:58
DRAGONAIR LV: 56
DRAGONAIR LV: 56
AERODACTYL LV: 60
DRAGONITE LV: 62
RECOMMENDATIONS: ARTICUNO LV:60 OR HIGHER
#5:YOUR RIVAL
POKEMON:
PIDGEOT LV: 61
ALAKAZAM LV: 59
RHYDON LV: 61
YOUR RIVAL WILL HAVE OTHER POKEMON FOR EACH OF YOUR BEGINNER POKEMON
RECOMMENDATIONS: ALAKAZAM LV: 70 OR HIGHER AND GENGAR LV:55 OR HIGHER