Hi,
If you post your with/without spouse scores it might be more informative.
No there are no consequences as such.
However, if you apply in express entry as single applicant and get the ITA, you might face difficulty in adding your spouse before submitting final documents for PR, as in your case I am assuming score will drop as soon as spouse is added and visa officer may refuse your case.
If you go ahead as a single applicant and get a PR just for yourself, you will have to sponsor your spouse after you get a PR, which can take a long time(1 year i suppose) as well as having other pre-requisites.
In my case, I applied as single applicant (CRS 443), got the ITA, added my spouse (CRS score with spouse = 446) BEFORE final submission and got a PPR last week. However, as you can see, my score with spouse was HIGHER than without, so i'm assuming it was not a problem.
So to surmise:
No consequences as such for applying as a single applicant. You DO have to submit police clearance and medical tests anyhow, whether your spouse is accompanying you or not in your application.
And as you rightly said, they may accompany you after an year after you successfully sponsor them.
That's my understanding, others may correct if wrong
Good luck!