New x5 3.0 owner - Head Gasket Concerns

[blatant]

Hi all,
I have been a lurker for a while on xoutpost but fairly active on bimmerforums and m3forum. I currently own an e46 m3, e36 m3 and recently acquired an e53 x5 3.0 2001.

The plan is to get rid of my e36 m3 and make the X my daily. I purchased the car this past Sunday with the impression the car needs its head gasket changed. I acquired it fairly cheap which makes either a head gasket swap or engine swap worthwhile.

Last night I tore into it. I drained coolant and oil. The oil was really black but I could not see water or coolant in it. The coolant on the other hand looked to have a good amount of oil in it. It was a mix of blue, green and oil. My impression is that the previous owner knew he had an issue, as I can tell there are all new hoses, radiator and thermostat....so that would lead me to think that he drove it around with the head gasket issue for a while.

I have completed 3 headgasket jobs on s50 + s52 engines but I have some concerns with the all aluminum m54.

1. Since the x5 most likely has been driven for a while with the head gasket issue, am I more than likely going to have an issue with the head bolts stripping in the aluminum block?
2. I have never timeserted before, so that concerns me. How difficult is it?
3. The coolant system has oil in it now, including the heater core. Has anyone ever used a cleaner to get rid of the oil? What is a procedure I should follow to clean out the system?
4. I have not run a compression test (have it) or leak down (do not have), would anyone recommend doing this before I tear into doing the head gasket job? The amount of oil in the cooling system made me just jump to "change the head gasket" mode. Like...can power steering leak into radiator.

I'd appreciate any help with this.