The doctor explains the ICF to the translator who in turn explains the ICF to the subject in a language the subject understands. But the translator signs in place of a witness. Is this acceptable?

 
It depends on who the translator is. If he/she is site person, he/she cannot be considered an impartial witness. If he/she is a relative/friend of the subject, he/she can be considered an impartial witness.

It is also important to consider how the PI manages such a situation in his practice. If he cannot talk in patient's language, how does he diagnose/treat the patient? If he does not manage such patients in his clinical practice, why does he include them in a trial?

In a bioequivalence study, a subject was found to have raised 'Random Blood Glucose' level. Hence an AE was hence filled. After 15 days, repeat blood glucose confirmed that the subject had Diabetes Mellitus. As this is a long term disease, when does one consider the AE to be resolved?
ICH B 2 recommends several outcomes.
B.2.i.8 Outcome of reaction/ event at the time of last observation

• recovered/resolved
• recovering/resolving
• not recovered/not resolved
• recovered/resolved with sequelae
• fatal
• unknown

Considering the nature of AE, not recovered/not resolved is an appropriate option.

One of the criteria of seriousness is - other medically important condition.
ICH EA Medical and scientific judgement should be exercised in deciding whether expedited reporting is appropriate in other situations, such as important medical events that may not be immediately life-threatening or result in death or hospitalization but may jeopardize the patient or may require intervention to prevent one of the other outcomes listed in the definition above.  These should also usually be considered serious.

The current AE would quality for this classification and can be considered SAE.

Can a medical graduate without specialization, but with enough experience as a Medical Investigator will be eligible to be a Primary Investigator in BA/BE studies?

CDSCO BE guidelines describe as follows:

• An investigator who has overall responsibility to provide of the human subjects
• An investigator should possess appropriate medical qualifications and relevant experience for conducting pharmacokinetic studies

Compliance Programme Guidance Manual For FDA Staff   Chapter 48 Bioresearch Monitoring Human Drugs In Vivo Bioequivalence:
The clinical investigator in a bioequivalence study is involved in the screening and dosing of human subjects, and will ordinarily be a physician. Ph.D. clinical pharmacologists and Pharm.D.'s are acceptable if a physician is available to cover medical emergencies. The clinical investigator may also perform pharmacodynamic measurement(s) and evaluation activities of clinical or pharmacological endpoints

None of the guidelines recommend a specific qualification e.g. clinical pharmacology. Hence, an MBBS who has relevant experience to take overall responsibility as investigator / can perform all duties of an investigator can become an investigator for BA/BE studies.

Can a nurse can play the role of lay person in an EC quorum?

Lay person by definition is someone who is not an expert in any field.
Nonscientist - Members whose training, background, and occupation would incline them to view research activities from a standpoint outside of any biomedical or behavioral scientific discipline should be considered a nonscientist.

Considering both these definitions, a nurse would not qualify as a lay person as his/her opinions will be based on biomedical knowledge.