They wouldn't like to, but they are ideologically close to SYRIZA as a Socialist party and would not have much of a choice, if there was a pure left wing majority. If they blocked a SYRIZA government they would be destroyed in the next election.
ANEL on the other hand is a right wing protest party, that would never join or support any government, especially not one with a Socialist party as the leading force.
This is definitely wrong on ANEL (and on DIMAR, to some extent). At the last election, ANEL and DIMAR all but campaigned on a coalition with SYRIZA. Neither would be unhappy about working with SYRIZA, though of course ANEL would rather their anti-austerity coalition partner were on the right (and probably prefers XA to SYRIZA as an ally). DIMAR would rather lead the coalition, but they wouldn't object to joining up with SYRIZA. (I'm somewhat surprised that they're even surviving--they were initially the anti-austerity center-left splinter, so joining a pro-austerity coalition should have killed them.)
What a party campaigns on and what they really want are two different things.
A coalition with SYRIZA with their radical socialist platform would be a nightmare for ANEL and end in a meltdown for the party. I doubt very much that the ANEL leadership really wants to form a government. It is basically a populist party which has no real solutions to anything and this would be revealed if they ever came to power. But this is of course my interpretation, not something I can prove.
I just think you are making the mistake of treating ANEL as a serious party and not as a career vehicle for its leadership.
Regarding DIMAR I think we basically agree.
A. They are interested in a left wing government, but don't really want to be the junior partner in a SYRIZA led government (because they want to be the dominant left wing party and don't really trust SYRIZAS leadership).
B: If its necessary for them to let SYRIZA lead the government (which it will be) in order not to block the possibility of a left wing government, they will reluctantly do so.
