I believe since this is an ICT WP, we are on an LMIA Exempt job.
We are keen to apply for the PR and his company has offered a full-time permanent job for him.
With this , can we claim 50 points for Job offer since his job is LMIA exempt?
Since it is LMIA-exempt and ICT, your husband would have to work for a full year (52 weeks) in Canada before being able to claim the arranged employment points. It would then also make him eligible to apply under the CEC class.
Secondly job letter from our company is sufficient?
You would need two different letters from your company.
One, for all work experience claimed for points, a reference letter is required attesting to the work experience already gained.
Second, to meet the requirements of having a valid job offer, your husband would have to have the offer of permanent employment (after obtaining PR status) as a written job offer.
Yes, both letters can be combined into one, as long as both sets of information requirements are met, but then you upload the same letter twice. Sometimes it is just easier to get two different letters (depending on the employer), just to be sure.