Too many questions!
Although the aircraft may meet FAA requirements, a lot depends on when any AD become due.
You could take the aircraft & find that numerous ADs are required on both airframe & engines requiring shop visit. What life is remaining on the gear? This should be picked you by the company leasing the aircraft. Also you need to check JAR Ops compliance dates as compared to FAA.
As already pointed out a through reveiw of the records & AD compliance will give you a good idea. All ADs are available form FAA web site.
Seats & saftey equipment being a big problem mainly due long leadtime for seats, different overwing requirements / seat construction to FAA requirement.
As for actual maintenance cost, this will depend on bridging check requirements, out of phase etc. Often repairs need to be re-done as ones on the aircraft do not comply with SRM etc. Has the aircraft been surveyed?
Who is aligning the maintenance schedule? They should be able to give you a breakdown of tasks that will need to be carried out apart from the current planned check.
Could spend hours but no time. If you have more detailed questions we can work out a fee!
