Should be no problem. Just make sure you bring the proper paperwork to the US so that they indeed have proof that you passed the exams. This might actually mean a package straight from your UK school to the US school so that you cannot tamper with its contents.
There is no particular order to the exams. Take them in any order you please. The schools in the USA also don't bother with the "met before solo, nav before x-country solo" quasi-rule: In the US you'll be flying solo on an FAA student pilot certificate, and the FAA mandates a rather simple pre-solo exam.