1. Donee need not hold it for 3 years as holding period would be the same as that of the donor
2. But be cautious, while you sell your flats, bonds should be available at that point of time.i.e. You may also note that the investment in bonds for the purpose of claiming exemption under Section 54EC has to be made within six months from the date of transfer of the capital asset for the purpose of benefiting from the exemption under Section 54EC. Even if bonds are not notified and if you are unable to invest within the stipulated time due to this reason, the benefit of the exemption under Section 54EC would be lost.
3. Yes the income of cg after allowing exemption u/s 54ec will be clubbed in the hands of spouse.(here you).
Refering this case law for claiming exemption u/s 54ec
DCIT v. Rajeev Goyal
Capital gains – Investment in bonds – Beneficial owners – Clubbing of income –
Separate exemption is available in respect of income clubbed under section 64 [S. 64]
The assessee earned long term capital gain on sale of shares. The two children of assessee, being beneficial owners also earned LTCG on sale of beneficial shares. The assessee along with his minor children invested amount of long term capital gain in REC bonds and claimed deduction under section 54EC. The Assessing Officer clubbed the income of the minor children in the hands of the assessee but disallowed the claim of deduction on account of minor children. It was held that in case of clubbing of minor/ spouse, all deductions are to be allowed while computing income of minor/spouse and only net taxable income to be clubbed under section 64. Therefore, where income of assessee’s minor children was clubbed with his income, assessee was eligible for deduction under section 54EC on investment in REC capital gain bonds on account of minor’s income from long term capital gains separately. (A.Y. 2007-08)