hey man. im glad i helped with the flashing.
i gave you some info before (http://forum.xda-developers.com/show...1165560&page=2
) on what those things are.
specifically, root allows you to change things on your phone that you normally couldnt. it could make it better..or you can brick it if you dont know what you are doing.
since you are not programming or modding, being deodexed shouldnt affect you too much; same for busybox. having them is only a plus but i you dont do anything directly involving them. you need busybox and once you root using superoneclick, you usually have it, so just know you need it and read that link i gave you.
bloat are those extra tmobile programs. many people dont like them because we dont use it and it takes up space, but some people find them useful.
when flashing a new custom rom, you probably wont get ota updates because the fota files are removed, because they take up a ton of space that you dont use 99% of the time. if you are on a stock rom, i think you can still update through kies, but honestly, i will probably never use kies again because this community updates faster and better roms than tmobile. even when the gingerbread update is officially released, i rather stay with teamwhiskey or team acid's roms until they decide to release something because i think their stuff is much better than whatever tmobile can come up with.
do you have any specific questions about the things you listed? or anything in general? we're all here to help
If I helped you, the thanks button is very much appreciated.