Well that is very hard to say that what exactly would be your PR because its Google's algorithm and only Google knows that. But it will do some good to you for sure.
Google is updating pagerank once or twice in a year and even we dont know when. I am sure it wont help much as it wont be permanent links, its only for 3 months but if you increase your time period, I am sure you will get good fruits (have link at least for 1 year).
The link from the PR 5 site will be consider as quality back link. Googe will give more preference to that link.
link juice that passes through a page is not just dependent on the PR of that specific page but also on how many outbound links that page has. if you have a backlink from PR5 page and your link is the only outgoing link that page has, you will very likely get a PR3 in the next one or 2 update. however, if the PR5 page has 300 outgoing links (many so called high PR link sellers find dormant high PR blog posts and keep spamming those pages with spam comments), then you will not get any link juice passed to your site at all as all the PR juice is being divided by all the outgoing links that page has. google usually update PR once in every 3 months or so and how long you had the links before the PR update also has something to do with it. if google didn't find your links long before the update, then you will not get any benefit in the coming update.
You MIGHT reach PR1. But again, PR is varied through various factors which are unknown to us at this point.
Relevant backlinks are main factor. If you have got relevant backlinks then its possibility to get pagerank 2
Stop wasting time/resources with PR and for PR ... PR is just a number nothing more and is updated very rare by google like 5-8 months once ....
I have tested it myself. Link to high PR sites will surely give you credits. It really works. But of course, you should analyze your keywords first... competition etc.
I suppose it will boost serp as well. you are at a time adding 5 high quality PR sites. be careful~! they must not look spammy.
there is a website with about 3,000,000 backlinks but it's pagerank is still 0 ! the website is for a blog template designer and many blogs and websites links it through a link which is at footer of template . but pagerank is 0 !?
What's also important is to check whether the site that links to you is contextually close to your site. So, for example, if you have a "Ringtones" website, contextually close links would be links from mobile phones websites, music websites, mobile content website etc. The PR 0 situation can happen because of many different reasons, it's impossible to find a specific reason without checking the site out.