Assuming you have the front axle hubs unlocked and are in 2WD (2H) the front end should not have any impact on any shimmy. Front driveshaft and axle shafts should not be turning under those conditions.

You should fix the leaking axle and knuckle seals, left too long and the gear oil leaking out of the axle into the knuckles will wash the grease out of the birfield and wheel bearings and they can start to wear faster than normal.