Shaft in Gearbox (static analysis)

In this case, we have a two-stage gear assembly where intermediate gears (3 & 4) are mounted on a transfer housing. This transfer housing is fitted onto a stationary shaft, which is supported by two bearings. The stationary shaft itself is aligned on two holders, also using two additional bearings.

The current arrangement of the outer single-row bearing is causing a preload on our transfer housing. This preload is transmitted from a sleeve to a nut and then to the inner single-row ball bearing, which functions as a sliding bearing. The other bearing on the transfer housing acts as a fixed bearing. 

The purpose is to optimize and reduce the weight of this transfer housing, so the analysis is supposed to be done only on the transfer housing.

The calculation of the gear forces and fitment of bearing and gears on the housing is as below. But the problem is when I define force on one tooth, should I define contact interference or I just omit the teeth and consider a disk with pitch diameter ?

the other question is for the definition of the fixed and sliding bearing I idealize a point as an infinitely stiff spring (Point-surface) and connect it with the weighted link to the contacting circumference area of bearings and housing, but after that for the fitment pressure from bearing I exert the force on this same surface or it is wrong ? 

Force F23: [-242.65, 626.46, -228.01] N ,  %[Fr, Ft, Fa]
Force F54: [-181.99, -469.85, -171.01] N , %[Fr, Ft, Fa]
Force at bearing C: [808.04, -626.46, 399.02] N
Force at bearing 😧 [-383.41, 469.85, 0.00] N
Fitment Pressure for gear 3: 14.39 MPa
Fitment Pressure for bearing C: 30.15 MPa
Fitment Pressure for gear 4: 7.79 MPa
Fitment Pressure for bearing 😧 33.29 MPa