Resurrecting a dead post again here ......
No, Paul was not alive at the coming of the Lord. He didn't want to be. He desired to be dead before then, so that he could participate in the resurrection. For proof of this, read his words in Philippians 3:9-11. These verses are preceded by Paul giving a list of his credentials in Phil 3:4-6 (a "Hebrew of the Hebrews", "circumcised the eighth day", etc.). He then says that he was willing to chuck all of these qualifications in his resume - that they meant nothing compared to being wrapped in Christ's righteousness. This alone would be what would entitle him to participate in the "power of His resurrection" (Phil. 3:10).
Here are Paul's words in the Phil. 3:9-11 Interlinear version that show Paul wished for his own death to occur before Christ's coming. "...and be found in him, not having my righteousness which [is] of law, but that which by faith of Christ [is], the of God righteousness on faith, to know him and the power of resurrection his, and the fellowship of his sufferings, being conformed to his death, If BY ANY MEANS I MAY ARRIVE AT THE RESURRECTION OF THE DEAD." If at all possible, Paul wanted to be dead so that he could "arrive at" the time when the resurrection of the dead saints occurred at Christ's coming.
Did Paul have an idea of the time when his own death and the resurrection would both occur? Yes, he did. Remember, God had told Ananias in Acts 9:16 that He would show Paul "what great things he must suffer for my name's sake". That list of "great things" God showed him would include Paul's martyrdom also. Check out Paul's words in II Timothy 4:1-2a, 6-8 (Interlinear) as Paul sent Timothy his last words from a Roman prison prior to his martyrdom under Nero. "Earnestly testify therefore I before God and the Lord Jesus Christ, WHO IS ABOUT TO JUDGE LIVING AND DEAD according to His appearing and kingdom his, proclaim the word; be urgent in season, out of season, convict, rebuke, encourage...." This proves that the resurrection and the appearing of the Lord Jesus was imminent as he wrote those words to Timothy. He was stressing to Timothy the need for evangelistic urgency because of the soon-coming appearance of Christ.
Then Paul mentions his own fast-approaching death in II Tim. 4:6-9 (Interlinear). "For I already am being poured out, and the time (kairos - season) of my release is come. The combat good I have combated, the course I have finished, the faith I have kept. Henceforth is laid up for me the of righteousness crown, which will render to me the Lord in that day the righteous judge; (the day mentioned in II Tim. 4:1 in which the dead were about to be judged) and not only to me, but also to all who love his appearing. Be diligent to come to me quickly..." The urgency of Paul's words, wishing Timothy "to come before winter" (II Tim. 4:21) and to bring with him the books, the parchments, and the cloak that Paul had left at Troas (II Tim 4:13), shows that this letter to Timothy had to have been written just before winter in AD 66. Paul was martyred in June of AD 67. The resurrection and Christ's appearing happened at Pentecost in AD 70.
Paul may not have known the exact day or the hour of the Lord's appearing beforehand, but he had been told all the signs to look for. We have his record of these signs passed on to the church in II Thessalonians 2, where Paul reminded them of what he had already discussed with them in person. I Thessalonians 5:1 says that the Thessalonians were well aware of "the times and the seasons" of the Day of the Lord, so that it would not overtake them unexpectedly. This was an event that the first-century generation looked for, and would experience in their days.
When Paul spoke in I Thess. 4:15 and 17 of "WE who are alive and remain", he was NOT saying that he expected to be alive at Christ's coming. He was merely speaking as a representative of the church. "Those of our number who are alive and remain" is his intended meaning. It would be the same as a male pastor standing up in front of the church and announcing "WE will have a ladies meeting this coming Wednesday". Is that male pastor including himself as one of the women, and will he be attending the ladies meeting that Wednesday? Hardly.