Making classified site with few specific questions, please advice if you know

Hi, I want to create classified ads site using WordPress Cms. Lets say it will be real estate classified ad site. I have

few questions:

1. I want people being able to submit their ad, but only registered users. They register through wordpress FRONT END and

post their ad. I want ads to be shown on site only after I aprove them. IMPORTANT – is it possible to allow them to

EDIT/DELETE their ad after its aproved and posted online? Especially I want them to be able to delete their ads.

2. I want to hide some details from non registered users. For instance I want to hide contact info of all advertisments

from non registered public. For example you visit the site, see nice ad and you want to call them. But you can not see

contact info of that ad if you are not registeted. You must register in order to view that info. Is that possible? How? Any

plugins to be used in order to make this happen or this is simple code for WP developer?

3. Can they upload images? How is that done? I mean they don’t have access to my ftp, so how do they upload? For example

they submit ad of the house they sell, how do they upload pictures of it?

4. People submit pictures of various dimensions – horizontal, vertical photos etc. How do I unite them. Lets say I decide

that my thubs will be all the size of 200*200pix, and when you click you get to the bigger picture. But how do I make this

happen so that thumbs would look nice and not streched out. I mean thumb is square and if someone submits 300*900 pix photo

and it gets resized to 200*200 won’t it be streched in some way? How do I make unified resizing nice and easy?

Please reply if you have any ideas about any of these questions, I am not expert so some may sound stupid, but anyway ??
Cheers