1. If the Sol player is hit by the "Sol Offensive" card they may move their units to any one space on the board. Does this include spaces occupied by enemy forces? What about allied forces? This creates an odd timing issue as these units don't fight until the battle phase (presumably) which seems weird...especially if Sol and allied units share a space in the battle phase.
There is no clarification or rule example currently available that answers this question that I have found definitively. The only thing to do is apply logic to the best of our abilities and use other related rules. A couple can be answered using other rules.
In regards to allied forces the answer is no. Page 15 under Effects of an Alliance is quite clear “Players cannot deploy or move units in a space where one of their allies already has units”
As for enemy forces I would say yes you can. I would treat is as if it was a deployment like any other, the only difference in this case is that the units will share a space for a few extra phases, but because the collection phase is last in a round the conflict will be resolved before it makes a difference. Just like in the battle phase an area is considered not controlled until the battle is resolved, so as far as winning conditions go the space is not controlled by either player until after the battle phase.
2. The Hacan and their allies may instead of deploying units move units from one space to any other space on the board for 1 influence each. Can they do this to spaces occupied by other players (enemy or allied)?
I think the same rules apply that being just use normal deployment rules, no for deploying on allied spaces, yes for enemy spaces.
3. Not a movement question, but putting it here, the Lazax is allowed to give his allies influence before they bid on a card;. The ally card says he can do this once per turn. Is this once for each ally (they each have their own ally card) or once total per turn?
Since each ally has their own ally card, it makes sense to me that it would be once per turn separately for each ally, so he could do it twice, once for each ally.
4. This is more a strategy question than a rules question. In our game the Hacan, Sol, and Jol-nar allied against the Lazax, Xxcha, and Barony. The Lazax team had at various times eradicated all units of the other 3 races. In the end the Lazax held two strongholds, and the Xxcha and Barony each held one. Jol-nar had the last and had just deployed his entire force (20 units) to sit on that stronghold (thanks to some recruitment cards he was able to see and auction for). I am unsure how the Lazax team evicts the Jol-nar while protecting their strongholds from the Hacan and Sol. Especially since their is now way (that I'm aware of ) for two allies to team up to attack the same space. Time was running short and the Sol/Hacan were simply trying to draw out the game to win with their races victory conditions...I'm not sure what the Lazax team should of done to acquire that 5th stronghold.
This falls under the “working as intended” department of rules. The disadvantage of being in an alliance is that you must coordinate your attacks, but cannot wage battles together. This is a critical element of ensuring that alliances are less about double or triple teaming and more about coordinated efforts to win. My suggestion is, don’t get into these kind of alliances and if you do make sure it’s in the final moments with a firm plan in place on how you are going to steal the win from them, but even than I would be weary of treachery. Maybe its my own group dynamic but I don't trust my allies anymore than I trust my enemies and I only go into alliances when it serves me. I can't imagine a scenario in which I would find myself in a 3 man alliance, way too many complications and way too many ways to get screwed. You have discovered one of many such examples.