1.) “Christ has been raised out from-among the dead, the Firstfruit of those who are reposing.” The term “Firstfruit” promises that at the minimum there will be others afterward; and the cultural connotation is that of a promise from God that all the harvest will certainly follow. (It is for gratitude about this promise that the Firstfruit offering is made.) This is a promise of ideal persistence from God; the open question would be how large a harvest is intended, not whether the harvest will succeed. (This is also, by the way, an undisputed and non-contentious example of process: first Christ then all the rest of the harvest later, however much that is.)
2.) “For since in fact through a human came death, through a human also comes the resurrection of the dead.” The ‘for’ connects this thought as an explanation of the implications of the previous verse. A next logical question would be whether, by comparing Christ to Adam in this way, Paul really means to compare the relative scopes of condemnation and salvation as being on par with each other.
3.) “For even as in Adam all are dying, thus also in Christ shall all be vivified.” The line of thought continues with another ‘for’, and appears to emphatically affirm the scope that the prior verse might have suggested: even as all die in Adam, thus also shall all be brought to life in Christ. The scope of what all means in the first clause dictates the comparative scope of what all means in the second clause, by means of the “even as / thus also” comparison. But while people are presently dying (present tense) in Adam, all being made alive in Christ is something expected in the future. The persons in a historical fashion indicate a process, but the verbs even moreso.
4.) “Yet each [shall be vivified per the preceding verse] in his own class.” Again a process.
5.) The sequence begins with Christ the Firstfruit.
6.) Thereupon {epeita} the ones of Christ in His presence. The term, although relatively rare in the NT (about a dozen occurrences but across numerous ‘families’), is indisputably an adverb of sequence, and in fact is an even stronger version (‘on-after’) version of a more standard (but also relatively uncommon) adverb of sequence {eita}. Paul is going out of his way to emphasize the sequential process, and even appears to be indicating a logical connection between them: because Christ is vivified, so shall be the ones in His presence. The latter is explicitly grounded “on” the former.
7.) Thereupon {epeita} the consummation. This is a bit more vague, and might depend on what “the ones in His presence” previously mentioned means. The departed spirits already with Christ? All the ones belonging to Christ (and so in that sense already in His presence)? The same strong progressional adverb is used as before, implying a causal sequence of some sort, too: the ones belonging to Christ contribute to the bringing-to-life of the consummation. The “thereupon” directly points to the “consummation”, whatever that means, being a third class of those being vivified.
8.) Although Paul does not (here anyway) explain who the “consummation” are who shall be brought to life after (and partially thanks to) the ones who are of Christ in His presence, Paul does give some idea next of when this consummation will happen: “whenever He [Christ] shall be giving up the kingdom to His God and Father” and “whenever He should be nullifying every sovereignty and every authority and power.” Until that happens, or has happened, the consummation will not be vivified.
9.) “For He [Christ] must be reigning until this one should be placing all His enemies under His feet. The last enemy is being abolished: the death.” Whatever “the death” means, it is the final enemy and is being abolished at the time Paul is writing, but is not yet under the feet of Christ in some significant fashion. Similarly Christ is reigning right now, but shall stop reigning in some significant fashion when all enemies, including the final enemy, are placed under His feet in some way that they are not already under His feet. This all points directly to a continuing process, that will not be finished in some significant way until after the being-brought-to-life of those who are in the presence of Christ. Notably, after indicating a third class of those who are being vivified (apparently thanks in part to help from those who belong to Christ in His presence), Paul has not spoken of anyone but rebel entities who still have some kind of status change to be made before Christ can stop reigning (in some significant fashion) and give up the kingdom to the Father (in some fashion He is not already giving it to the Father); and indeed the status of these rebels has to change before the “consummation” can be “vivified”. What is this status change? The rebels have to come under the dominion of Christ in some way that they were not already during the reigning of Christ. Once that happens, Christ will stop reigning in some sense; not until then.
10.) “For He subjects all under His feet.” Paul goes on to clarify after this, that this does not mean the Father is subject to Christ of course. But the implication is that all other persons are under His feet. That includes those who belong to Christ!–being subjected under His feet is not inherently a hurtful or hopeless thing. This is reinforced by the next statement, too.
11.) “Now, whenever the all may be subjected to Him, then the Son Himself also shall be subjected to the One Who subjects the all to Him, so that the God may be all in all.” Again there’s a process: first the all must be subjected to Christ, in some fashion that the all is not already subjected to Christ and has not already been subjected to Christ at the bringing-to-life of those who are already in Christ’s presence. Then Christ subjects the all to the Father, in some way that the all is not already subjected to the Father!–the result being that God will be all in all, in some way that God is not yet all in all.