kenwood and pioneer would be your best choices out of those.
oh yeh and both have detachable faces but watch out because those have one set of preouts which will not do any good if you want to power your subs and your front/rear comps.
nope just go with the one they suggested you. or look for a used alpine or eclipse on here. theres also a high end fusion head unit in the classifieds has a lot of nice features you would like.
looks pretty good. ive never owned a jvc. a couple people that own them say they are pretty good quality and under rated. looks like a good starter. i would still reccomend going with a higher end unit but if not something like this would work.