If the purpose is mainly to archive something: Why not just keep a copy of the original? Your opinion of "what is best" may change over time, so the best starting point for any future processing is always the original rather than some pre-processed version which you may find later that it has its own flaws which you cannot reverse.
Upscaling or resizing: Why do you want to upscale? Unless there is a technical need (e.g. standards compliance), keep in mind that upscaling does not add any real details to the footage. It rather blows up the width x height of the frame i.e. it is mainly a waste of storage capacity and/or bandwidth.
1080i conversion to 1080p: What is wrong with the 1080i format? Conversion to 1080p makes sense if you are sure that the original video is actually progressive and just encoded as interlaced for the sake of standards compliance. Otherwise, why giving up the double temporal resolution of the interlaced footage, or doubling the frame rate and file size with some kind of bobbing?
Again: for archiving, keep the original. Process the material for your actual use however you want, but don't "substitute" the original.
Just my 2 Cents
