How would you handle these tenants?

[Bienes Raices]

I started another thread about this, but now it's taken a new twist.

I had three roommates living together paying $850/mo. (total). One of the roommates moved out with little notice in mid October.

I was prepared for the worst, but the two remaining tenants were able to come up with November's rent on time on their own. However, they only paid $600/mo. at their last place so I'm not sure if they will be able to keep this up.

Then one of the two remaining tenants sent me an email hinting indirectly about what would happen to the security deposit if they had to move out before the end of the lease.

I am thinking of two options:

1) telling them I will let them out of the lease early if they stay at least until January 1st (so I don't have to deal with the holiday vacancy problem) and stay current on the rent until then, and I will give them back the deposit if the place is in broom clean, undamaged condition, as per the lease.

2) lower the rent to $800 to keep them there (I haven't had any real issues with the two remaining people, and they are taking good care of the place).

The thing that concerns me about Option 2 is that I still don't know for sure if they can consistently come up with the full $800/mo. or not. And I don't know whether I would have to start a new lease with them or if I could change the rent on the existing lease.
Also I don't know if lowering the rent could cause issues with a potential eviction if they can't come up with the $800/mo.. $800/mo. is absolutely the lowest I would be willing to go with the rent.

So would you do Option 1 or Option 2?