combining mixed framerates & footage

Hi all,

I would like to streamline my working methods with Premiere (I've used it for a long time but I might be doing things wrong).

Urgent matters:

1) I work on Panasonic camcorders that can record 1080/50fps (I work in Europe in the PAL region). What are the real benefits of recording 50fps rather than 25fps? I need to consider this as my current editing setup struggles a bit with 50fps but this footage might be used in the years to come too (documentary material) so would make sense to go for the best quality.

2) Currently I am combining two kinds of footage: 1080/50fps with 2.7K/30fps from my new drone (wrong settings!) and wonder what timeline settings I should use? Or should I do something with the 2.7K/30fps drone footage before importing it into the project / dropping it onto the timeline?
3) I have now changed the drone settings to 2.7K/25fps which I understad is better as I'm in the PAL region and using 50fps (or 25fps). When I start combining 1080/50fps and 2.7K/25fps footage, would you recommend 50fps or 25fps timeline settings? Which footage would you create the timeline with? Anything else I should consider?

For later on:

I will be editing a long project shot over many years and the oldest footage is on miniDV-tapes. Any suggestions how I should capture those so that I can combine all of this messy mixture of videos....? I would like to use the tape material with 1080/25fps (majority of my footage) & 1080/50fps & latest drone footage 2.7K/30fps and 2.7K/25fps.... not ideal at all but surely do-able.... Any advice & suggestions you might have I would love to hear.

Many thanks,

Elisa