Yes this is perfectly possible and a great albeit tiring day in the hills.
No, ropes are not required unless there is snow cover in which case you might (depends on your skill level/experience) want to rope up on the CMD and some parts of the East Ridge up to CMD summit can be a bit hairy under v.heavy snow cover - in fact I backed off of this notionally easy ridge a few years ago as I was very wary of the risk of avalanche on the day of my climb.
The route down from the Mor/Beag bealach is v.steep - under icy conditions it may prove difficult.
Biggest problem at this time of year is daylight or rather lack of it - under summer conditions and starting from the Snowgoose cafe it took me about 8.5 hours to complete the circuit (AM summit, AB summit, CMD summit & BN summit) - four big peaks in a day is good going too.
I like the route descriptions on this forum - they are well balanced and informative.
The gibber factor rating is pretty cruddy though - one mans gibber is very different to anothers so they are meaningless - at least in my view.
As an example I've been up Tower Ridge several times and only felt moderately gibbery (?) on that slightly overhanging bit before the Great Tower yet I once felt extremely gibbery on a slippery slab with a big drop below on a simple scramble on Great Carrs in the Lakes.
PS: if I've got the location of the overhanging bit wrong on Tower Ridge please forgive me - it's a long route and it blurs in the memory - it's the bit where you climb off of a small ledge with a big drop beneath it and you have to reach up 7-8 feet or so at a slight outward angle. Much more nerve wracking when soloing than Tower Gap!