Hi Matt,
Interesting, I've not looked at the time length that Satan will be in the lake of Fire in this way. But this did occur to me, how long does it say Christ will reign.
Rev 11:15 And the seventh messenger did sound, and there came great voices in the heaven, saying, `The kingdoms of the world did become those of our Lord and of His Christ, and He shall reign to the ages of the ages!'
Again this phrase "ages of the ages." This states that is the length of time Christ will reign.
1Co 15:25 For He must reign till (G891) He has put all enemies under His feet.
G891 - achri achris
(of time) until or (of place) up to: - as far as, for, in (-to), till, (even, un-) to, until, while.
So what I'm seeing is that Satan will be in the lake of Fire until Christ has made all things subject to Him. Maybe Satan is the very last thing that Christ brings in subjection to Him and then He delivers all things to the Father.
1Co 15:24 Then comes the end, when He delivers the kingdom to God the Father, when He puts an end to all rule and all authority and power.
1Co 15:28 Now when all things are made subject to Him, then the Son Himself will also be subject to Him who put all things under Him, that God may be all in all.
mercy, peace and love
Kat