The question was "is it biblical to pray in regards to someones salvation, and what would you consider and do in the warring (mindset and application of prayer)"
Then the first level is to make everyone clear that your prayer does not make their spirit and the Holy Spirit unite within them, forgiving their sins.
We so often spend so much time on these 'disclaimers.'
So then after determining what exactly we mean, we can get to the actual point of the question, which is "In addition to talking to someone, is introducing prayer into the equation a worthwhile and biblical cause? and what things do we consider when 'warring' " So since we war with a sword, the WORD (we dont war with our shield) what verses apply?
And so scriptures about preaching the gospel, and leading someone to the Lord are not in question, those scriptures will only cause to add to the first level, of what makes a Christian born again, and what is witnessing. So we can then look to scriptures about prayer, and about God's will, and about places in the Bible (I like choosing from the New Testament) where cases like this were made.
This is why I chose those references. If something is not clearly shown in scripture, we can look at how Jesus and His disciples reacted, and if we don't have a problem with it, we can learn from it, and choose to do the same.
And here are explanations for the simple. (Not my words)
"Many receive not because they ask not." That is a quote form God's word. If I were to use Brad's word, I would say that the reason that many dont get something, is because they never ask for it. Yet another way to say it is that without asking for things, you might never get them. In this case, I am referring to the fact that our prayers affect situations, scenarios, angels and their missions and comissions, devils, God's heart and actions, etc. And if God's heart is for salvation, then our prayers to affect the scenarios around ones life toward hearing and experiencing salvation is NOT an uphill battle.
For a more deeper revelation of that verse in regards to this topic: "Many receive not their friends and family into salvation because they ask not for their friends and families to receive salvation."
Philippians 1:19 For I know that this shall turn to my salvation through your prayer, and the supply of the Spirit of Jesus Christ,
The ace up my sleeve, was a LITERAL place in scripture where Paul said that part of his salvation was due to other peoples prayers in conjunction with the workings of Jesus. Here we have an exact, clear and precise example of the guy who God chose to write most of the New Covenant specifically saying that at least some portion of God's salvation was somewhat due to the prayers of others. (And again, to spend more time with disclaimers, as noted in the previous post, personal born again status is not the salvation that Paul was talking about here, but rather a different aspect of God's saving ways - and He has many areas of salvation to body soul and spirit) Any idea that says that you should not pray for the salvation of anyone goes directly against what Paul was saying there.
Here we have a direct example in the life of Paul, in his own words, about EXACTLY what we are talking about. It is clear and literal and easy to understand. I love when God does that.
And all we needed to do was define the hindering ideas, define the actual question, and then look up scripture that addresses the actual question, not get off on a trail that leads us away from the answer.
The answer: pray for people to get saved.