TDS on Salary

For 1st part of the ques the reply is for normal salary TDS should be paid till 7th of next month (even in march) but if there is any payment which is special like bonus etc. which is pending and a provision for same is created then May 31 will be last date. (with notification issued in may this date is changed to April 30 now.)

2. Salary paid to resident on which TDS is not deducted is still allowed as deduction. As Section 40(a) doesnt disallowed it.

addition to what shudhanshu said if you paid after the due date then it will be allowed in the period in which it is actually paid but it will be liable to interest

I dont agree with you as Section 40(a) is not attracted so there is no such requirement.