Ok - we "seem" to have a problem with the word "sitteth" as opposed to "standing."  But there really isn't a problem.  It is simply that sitteth and standing are used in two different contexts and both words are teaching us something.  Let's take a look.

         When one "sitteth," or "sits down" one has TAKEN UP A RESIDENCY!   When the antichrist "sitteth in the temple of God," he has seemingly "taken up residency" among them.  This is true as he himself will be seen and known as a "Christian" (that is, when he first appears... BEFORE he actually declares himself God!)  Also compare the antichrist's False Prophet with the "2 horns of a lamb", it is more than likely referring to a "form" of Christianity. The False prophet mirrors that of the antichrist, otherwise, he wouldn't be his prophet!

       You stated, "According to 2 Thess. 2:4 the son of perdition sitteth in the temple of God and doesn't stand in the midst as you stated."  But ask yourself this>  When the Antichrist "sitteth in the Temple of God," is it the same as the "Abomination that makes desolate?  NO.   All 2 Thess. 2:4 indicates is that the antichrist will sit (or take up residency) among God's people, who ARE the temple of the Living God ---(and btw, would the so-called "Tribulation Temple" REALLY be "God's Temple" anyway???)......AND it shows that by his "taking up this residency among God's people" he "shows himself that he is God."  See that?  He shows himself to be God.....HOW?>  Verse 9> "Even him, whose coming is after the working of Satan with all power and signs and lying wonders."  There he is, a professing Christian, taking his place among Believers, strengthening a covenant with Israel confirming their right to exist in the Land in peace & safety, and showing his (God granted) power and signs and lying wonders.
But 2 Thess. 2:4 says nothing about the "abomination."

       However, look at Mark 13:14> "But when ye shall see the abomination of desolation, spoken of by Daniel the prophet, STANDING where it ought not, (let him that readeth understand,) then let them that be in Judaea flee to the mountains:"

       When people see this antichrist STANDING WHERE IT OUGHT NOT TO BE, this so-called "Christian" declaring that he himself is "God", they'd better run!  When they are saying (1 Thess. 5:3) "peace and safety, then sudden destruction cometh upon them" they'd better heed the Lord's instruction to flee!
And considering the definitions of "abomination" and "desolation", Mark 13:14 could be paraphrased, "When you see the extreme hatred (the abomination) that manifests itself in blatant all-out persecution and killing of those who have true faith in God, (as opposed to those who do not have faith in God, for which God will allow them to believe a lie and come under strong delusion -to worship the antichrist as god) (and as verse 19 says, "For in those days shall be affliction, such as not from the beginning of Creation)...." then KNOW the "desolation" is at hand!

       In other words, the antichrist is going to try to render the "Temple of God" (whom ye are) completely unusable.  He will try to make them of no benefit, no witness, no profit, and of no good to God nor others.  HOW?  By getting rid of them!   And how about the Jews?  Well, he's always hated them for they are the chosen people through which Messiah came and will come (very shortly).

    I agree with you that your Scriptural examples teach that a Christian can "defile the temple of God" (the Christian's own body) through sin.   But Scripture has a multipurpose function.  ALL Scripture is "profitable for doctrine, for reproof, for correction, for instruction in righteousness."  There are natural
AND spiritual applications.  And yes, those Scriptures you quoted are profitable for reproof & correction, to show there are consequences for the sins done in our bodies; but IT IS CLEAR FROM GOD'S OWN WORDS THAT WE ARE INDEED THE TEMPLE IN WHICH HE DWELLS - "THE TEMPLE OF GOD WHOM YE ARE!"   I think when we understand this dual application in Scripture, it's easier, then, to understand it is also given for DOCTRINE.....the doctrine being that we are the Temple of the Living God whom we worship in spirit.

       Finally, as for Rev. 11:1-2, where John is told to "measure the temple" (and no measurements are able to be given because HOW do you measure Believers?) you said, "this may very well symbolize that the Christian believers in the temple of God up in heaven have been measured and judged....."...Well, this is not a reference to the Beama Seat Judgment.
The context is that of what is going on on earth.  The Temple of God (individual Believers) cannot be measured, but the Gentiles, those who are not believers, are left out.....don't even try to measure......for they are NOT overcomers, NOT God's people, NOR the Temple of the Living God because they do not have His Spirit and He does not dwell in them.

       I know we can only deal with one subject at a time, but as far as the Beama Seat Judgment, well, take a look at Rev. 15......think about what is shown there.  But that's for another post.
                                        Shalom,  Sherry Vance