I got as far as accepting joining the 5 companions. I don'the seem to have moved on to the next quest.
I read that accessing other alliances is achieved by defeating Malag Ball and then Caldwell offers the Silver and Gold questlines.
For me I found as soon as I hit level 50 and had champion rank, the Wayshrines for the other alliances showed up. I traveled to both and played some of the quests. I am up to almost CP 80 but any time I visit the Harbourage the conversations are still the same after 5 champions ones as before.
I didn't think anything was wrong because the quest in the Hollow City talks about going after Molag Ball so I thought it was all part of the same quest group. Now from what I read it sounds like both are separate and the guild wars really just go after Malag Bal's top minions.
Have I broken the main quest? Not the end of the world if I have as I still have Alts who can do it.
My Characters
Xargothius: Breton - JOAT / Magsorc | Orchid the Fair: Orismer - Crafter / Heavy Tank | Voneri Vox: Dunmer - Magplar Healer | Rexorgiana: Imperial - Temptress / Magblade
Phirkius: Altmer - MagSorc | Rexorigus: Imperial - Med Tank / StamKnight | Sven Svedishchef: Nord - Provisioner / Stamplar | Finds-All-Fungi: Argonian - Alchemist/ Stamblade
Emerald-Wild-Guard: Bosmer - Wyrd / StamSorc | Nates Datum Festi: Imperial - Light Tank / StamKnight | Magnolia Desert-Blossom: Redguard - 2 Handed Stamplar | Shadow-Softpaw: Khajiit - StamBlade
Sorcerer | Dragon Knight | Templar | Night Blade