I'm age 62. Can I collect Social Security benefits (not FRA til 66.6) while I wait for a determination on my SS Disability claim ? I understand this process takes some time as they collect medical verification. Will this early withdrawal adversely affect my disability benefit if I am approved ?
Secondly, is it worthwhile to hire a disability advocate (counsel) to move things along quicker ?
Yes, it's possible to draw reduced retirement benefits while your disability claim is pending. However, your benefit rate will be permanently reduced if you are paid for any months prior to your month of disability entitlement.
For example, say Bill has a full retirement age rate (PIA) of $2000 and he files for both reduced retirement benefits and disability benefits at age 62. Bill starts out getting his reduced retirement rate of $1500 while his disability claim is pending. Eventually, Bill's disability claim is approved with an onset date of age 62, but since there is a 5 month waiting period for disability benefits (https://www.ssa.gov/OP_Home/handbook/handbook.05/handbook-0502.html) Bill isn't eligible for disability benefits until he is age 66 & 5 months. Since Bill drew 5 months of reduced retirement benefits prior to his first month of disability entitlement, Bill's disability benefit rate would be $1944 instead of $2000. In other words, Bill would keep a roughly 2.8% reduction for drawing 5 months of reduced retirement benefits prior to converting to disability benefits.
I can't really advise you whether or not to appoint a representative to handle your disability claim. I don't think it would necessarily speed up the processing of your claim, but a good representative may be able to present your case in a more favorable light. The downside is that there would likely be a fee for the representative's service, which may be unnecessary if your claim would have been approved anyway.