A warning in advance:

I've had no problems linking records to get a non-status companion into E+ next to me, but if there is any sort of schedule or equipment change, the records will probably get unlinked and both of you could get sent off to weird E- or cargo-hold-quality seats.

With linked records, the old adage about checking the website often applies double. Last time I did this, I had to call to re-fix the seats no less than 3 times in the 5 weeks between booking and travel.