I am 27 years old and working in a software firm earning 5 lakh per annum.
* This is absolutely right time to take a term plan. You should take term plan as early as possible because at the age of 27 your premium will be less & after 2 or 3 years you might have to pay extra price for same plan. Also you should not compromise with your safety. Term Plan is not investment plan its for safety of your loved ones, so don't take any chance. Invest as soon as possible & live peaceful life

1- What will be ideal age for me to start the term Insurance? I have no liabilities.
I think i have explained this in 1st Question. its good you don't have any liability. You will get 1 crore term plan with a salary of 5 lakhs.

2- If I take multiple Term Insurance (from different companies), can a claim be made to all of them.

Yes u can claim from all them but you need to inform 2nd company that you already have term plan with so and so company. If not disclosed in documents that 2nd co. will not be liable to pay you.

For security take insurance policy & for investment plenty of options available in market.
All Insurance companies have term plan, you can check riders and benefits they are providing. Check plans of Max Life Insurance, Aviva India, Bharti Axa, Aegon