Is there anything to learn in the differences in "churches" and "church" as mentioned here?
These are not informal gathering groups.

v14 a group of some men who are in a role of leadership and those who are with them.

v15 another group

v16 "holy kiss" a sign of brotherly love
Luke 7:44,45  Luke 22:48

v17 the area of church discipline -- Matt 18 - shunning; 1Cor 5:9; 2Thess 3; Titus 3;  (02-07-28 PM Worship - "Harmony Through Purity; part two")

v18 this is not the "epicurean" lifestyle but addresses the center of what motivates. "Self-centeredness"