Chuck, I can't answer for all, but here are my personal answers.
1. Any and everyone is welcome. If you are not a member, you won't be asked to do things such as lead a prayer, lead song service, teach a class,etc. but will be more than welcome to participate in worship.
2. That's a tough one. Baptism is a serious subject. One must be scripturally baptized in order for it to be recognized--infant baptism, baptism
because you were saved, baptism in any other name but the Father, the Son, and the Holy Spirit, etc. is not considered scriptural.
3. Yes. Although there is no earthly leadership outside the elders of the individual congregations, congregations that can afford it, or sister congregations working together, do sponser missionaries, as commanded in Matthew 28:19,20.
Concerning the comments........
1. Exactly--shouldn't that be our only source of information concerning God and worship?
2. Honestly, that's not the purpose behind the lack of choirs, solos, or instruments. There is just no justification for such in New Testament worship. I do love to hear the songs where everyone joins in and the building accoustics are good, but it's not meant for our personal pleasure (I have to remind myself of that sometimes when, for whateverreason,it's not too pleasing to my ears).
3. Now and then there will be a sermon on giving--as it's part of the Bible and what we are commanded to do, I feel it should be brought up from time to time, to remind us that it is a command and what it's for. There is no emphasis on tithes--Christ told us to give as we have been prospered, which should equate to well over 10%. The Israelites didn't give just 10% of their money, they gave 10% of their herds, etc. also. It's not pressured--folks just seem to understand and do it. No idea what the preachers make--I'm sure it varies from one congregation to another. Most I know work a "regular" job as well as preach. On a side note, you won't hear the preachers referred to as "pastors"--they are called preachers or ministers or evangelist. The term pastor is used in referance to elders.
4. It happens, but is often reprimanded (as it should be). I've known of entire families leaving the congregation when this was brought to their attention.
Negatives.......I don't think anybody has cornered the market there. Everyone has their faults--I've been to different churches, Church of Christ and others, and with some the reception was as if you were family, some treated you like you had leprosy or were a spy or something. Sometimes both treatments came from the same congregation. One young preacher told me of a congregation he visited where the membership was generally pretty well off monetarily, and he was snubbed for not wearing a 3-piece suit and tie on either a Sunday night or Wednesday night service. I often wear jeans myself.
Chad