...also, dont worry about whether it is possible to complete the event f2p or not...

All other events so far could be done in about half the time given. All of them (Maybe the sexpedition type a bit less, however also easy to complete, also no AC needed for those).

Once they introduced a new type of event, it sometimes seemed impossible (like this time), but that just means some guys freak out, rage and then spend some rubies and then the devs relax the timing. they could give more tokens instead of 5, or speed the battery recharging or whatever.. calm down, there will be a patch soon and you will be able to complete easily...
If not, that would be the first time, well, then spend some rubies, get over it, there are hundreds of free rubies each week

As a long term player you already know (or learn it now), you should always have 1000 rubies left for things like that...