Get everything done that you can do immediately, while you are waiting for IELTS date: ECA, experience letters, police clearances etc. Go through the CIC website and the EE document checklist. You can do Medical exam after you get the ITA. Get the IELTS date quickly; not a ton of preparation is required; it’s like TOEFL but longer and slightly harder (check other questions on this forum regarding IELTS).
The best proof of funds are liquid assets like your bank accounts (checking/saving), fixed deposits in India etc (something that can be liquidated immediately). Based on some forums and some heresay, my understanding is that US 401k etc should also be acceptable, although I’m not sure if this is true or not.
Note that all these accounts should be in your name (or you+your wife joint account is acceptable if both are applying). For e.g., my FDs in India would not work coz they were joint under me and my parents so I couldn’t use them. So I just showed my bank statements and summaries.
Another option is to liquidate non-liquid assets and show those funds, although I’m not sure how this would work or if it’s acceptable (since you are suddenly getting an influx of cash; maybe add it to the letter of explanation (?)).
Get started of FBI clearance asap coz they will take time! (they’re probably already stressed 
)
Get the Indian embassy clearance done as well. Usually they’re quick but why wait… (note you will need passport the day of IELTS exam and you’ve to send passport to Indian embassy to get the clearance so don’t let them conflict).
Reference letters should be on company letterhead with all details, e.g. how long you worked, what exactly did you do. E.g. if you’re a software engineer it would be good to list the projects you worked on, the technologies you worked on, your general duties and responsibilities etc. Even if your previous manager has now moved to another company, ask them if they can give it on their current letterhead (my former US manager did so). These things take time as it’s highly dependent on when your manager responds to you so get started on that. I don’t think it’s necessary that the HR person should sign it if the manager’s signature is present. If a company refuses to give you one, get an unofficial letter from manager if you can, and your offer/resignation letters etc, with a letter of explanation and upload (it tells CIC that you tried to get one but failed).
As long as you get enough points and clear the cutoff to get the ITA, that’s all you really need; once you get ITA it’s all about if you have all the supporting documents needed and if you submit that before the deadline. If I’m correct, PNP requires that you live and work in that province already. I would try to get the EE ITA.
(The following information is based on my limited experience in Canada, and I welcome additional information from more experienced people)
Job market: Ontario (Toronto), and BC (Vancouver) are the two places for techies. although there are jobs in other provinces as well. In general jobs are limited in number as the population is low, the industry is not as matured as, say, Bay area, although that’s changing rapidly.
The further up you go, the colder it gets (check google maps and weather channel), although Toronto cold is not significantly different that Detroit cold!
Income, costs etc: From what I’ve seen and heard, salaries are not as high as they are in USA, even in absolute $ number. E.g., someone earning US$120k+ in Bay area might only get CAD$94k+ or something in Toronto; although this can vary a lot based on your profile, the cost of living, the company etc etc etc. Cost of living (especially housing) is high in Toronto just like any big cities in USA, and even higher in Vancouver. There are also lots of benefits in Canada that you don’t get in USA; e.g. universal healthcare, 1 yr maternity leave, no visa required to work, good retirement benefits etc. So there are obviously pros and cons to moving there.