J79 - you are clearly interested in thrust driven vehicles so let me help here in terms of engaging with the people on this forum.
First, most are well aware of the BloodhoundSSC project (even if their primary interest is wheel driven vehicles) so the links you've posted have already been covered and are old news. There is a thread elsewhere where any new stuff from them is referenced.
Second, the question you ask about why they've chosen a mixed power plant design is answered on their own website. Poke around a bit more and you'll find the answer - think it's in one of Andy's updates. As to the simpler jet or rocket designs you mention, well that's the beauty of having rules that encourage a multitude of solutions. There is no right or wrong way, only your way based on the your view of how best to solve the problem of going fast. And the only way of testing the validity of your solution is to build and run the vehicle and beat an existing record. If you hold a record, then that's the right way. Until somebody else comes along and beats it with a different solution.
The rotational effect you mention does exist and it did indeed cause Art some issues because he was a jet car pioneer so the extra forces exerted on wheel bearings, tyres and so on weren't fully understood back then by everybody. But other jet cars ran successfully and by now designers are well aware of it and know how to cater for it - hence Ed's succinct response.
Finally, most people here would use the word Turbine to describe an engine with a drive shaft attached to it. Yes they work on pretty much the same principles as a pure jet engine, but the exhaust gas driven output shaft connected to something makes it a turbine. the Turbinator team hold the current wheel driven record with a turbine engine. Sid knows a bit about this.
BloodhoundSSC and its predecessors Thrust2 and ThrustSSC use pure jets so Jet is the description they and most others would use.
Hope this helps.
Robin