Modern comms you're almost never going to have anyone identifying themselves by name, so that's a fairly non-problem, especially if your comms are primarily between other members of a 'Mech unit. The concept of an all-officer 'Mech corps is largely based on modern aircraft organization, which while it certainly has its merits is hardly the objectively correct way to do it.
Personally, I tend to organize ranks in such a way that a Lieutenant is leading a lance, a Captain (or Major) is leading a company, and a Lieutenant Colonel is leading a battalion. This means that within a lance you're going to end up with enlisted personnel, for which grade is determined by position and experience.
- MechWarriors with fewer than 90 days time in the unit that are 5/6 or worse are Privates.
- MechWarriors with greater than 90 days time in the unit or that have deployed in a combat action that are 5/6 or worse are Privates First Class.
- MechWarriors with greater than two years time in the unit that are worse in any way than 4/5, or with fewer than 90 days time in the unit at 4/5, are Corporals.
- MechWarriors with greater than 90 days time in the unit or that have deployed in a combat action that are 4/5 or better are Sergeants.
- MechWarriors with greater than 90 days time in the unit or that have deployed in a combat action that are 3/4 or better, or with greater than two years time in the unit that are 4/5 are Staff Sergeants; MechWarriors that occupy a lance second-in-command position that are worse than 4/5 may also be Staff Sergeants.
- MechWarriors that occupy the lance second-in-command position that are 4/5 or better are Sergeants First Clas.
- MechWarriors that occupy the company chief NCO position are First Sergeants.
- MechWarriors that occupy the battalion chief NCO position are Sergeants Major.
In this fashion one of my typical mercenary 'Mech companies of average Regular skill consists of 3-4 officers, 3-9 NCOs, and 0-6 junior enlisted. Junior enlisted tend not to stay that way for long, either due to attrition or to advancement. A typical mercenary 'Mech company of average Veteran skill or that has been on contract for more than ~three months tends to be almost entirely officers and NCOs.