As long as you have QuickTime installed, you simply need to import the files--Premiere Pro will have no problems with them.
Strictly speaking, you can edit your footage in any sequence preset that has the same general parameters as the footage without issue; actually, you can edit your footage in any sequence, but let's assume you want to at least match things like frame size and frame rate. You can use one of the existing presets (like the XDCAM preset), you can make a custom preset (click the Settings tab in the New Sequence dialog and set the Editing Mode to "Custom"), or you can simply drag your footage to the New Item button at the bottom of the Project Panel. This will create a sequence that matches your footage.
On a side note, if you can get the original footage, Premiere Pro will handle it natively--doesn't matter if it was MP4 or MOV, Pr will import and work with both perfectly well.
I am also working with Prores 422 footage by right clicking on the file and selecting "create new sequence from clip" The funny thing is that, when I go into the sequence settings, the format is never listed as Prores 422. This also happens with DSLR media, I let Premiere build a new sequence by draging the file onto the create new item icon and the resulting sequence will be "AVCHD" instead of DSLR. Is that something to worry about?
Is that something to worry about?
Nope, not really. The "Editing Modes" are really just shortcuts to setting up sequence to match (or more accurately, limit) parameters of the footage you'll be placing in the sequence. Premiere Pro really doesn't care about the container and codec of your footage--the most important considerations are things like frame size, frame rate, and field order. Since different video formats can share those characteristics, it really doesn't matter which sequence you use so long as those parameters jive.
For example, I use an AVC-Intra sequence or a Custom sequence with DVCPRO HD, AVCHD, and DSLR--and not one bit of AVC-Intra. The properties of my footage are usually all the same, so there is nothing too special going on--just drop it and edit it.
The one thing you might want to be conscious of is your preview file codec; if you set up a Custom sequence, you can choose the format and codec for rendered previews. If you want to use ProRes to render previews, for example, you'll probably have to create a sequence the long way, and specifically choose QuickTime as your format and ProRes as your codec. Those likely will not be automatically chosen, even when using a ProRes clip as the source to generate a sequence, so just pick a sequence preset as your starting point, change the Editing Mode to "Custom," and tweak as needed. Be sure to save your own custom preset so you can easily reuse it next time.
Hope that helps.