Lfr are watered down bosses of the current raid, less mechanics, low damage/healing/mitigation requirements, braindead cheap content for the casuals.
Alliance raids are entirely new Bosses, even though yes, they are on the easier side it's not to an extent that lfr had at some points where you literally could not die even if you tried to unless all healers where afk.
This is why as an former CE raider I can find alliance raids fun for 3-4 Id's but never could find fun in lfr (well except for the shitshows unfolding like on n'zoth.)
Btt: it's not only possible it's a really smooth and convenient experience with how leisurely character maintenance is and how easy it is to gear an alt, you'll have to get a msq and job boost though to skip the lengthy msq.