QUESTION 1-In the case of Microsoft Office Outlook Web Access, it does not look possible for gmail to access them. Gmail appears to need POP available, and my administrator says that without IMAP or better it is a waste of time. So you have to use microsoft explorer to access the web mail for the full set of options to appear and then set up a rule for forwarding or redirecting email to an address (instructions).

QUESTION 2-There are filters to add tags for organising the mails according to the to/from (etc) features or the emails.

QUESTION 3-Yes

QUESTION 4

1. Top right click on the cogwheel and on the parts that open below click on account settings
2. Below the word SETTINGS, click on the tab 'Accounts and Settings'
3. The section 'Send mail as' is the relevant section
4. click on 'Add another email address you own'
5. input the name you have on registered on your other email account (non-gmail) and the email address and click next
6. click on 'Send through strath.ac.uk SMTP servers'
7. you will need to put the username and password you use to access the non-gmail account and the SMTP Server address which may not be the default. The smtp address is usuall known to you if you set it up, or ask the admin somehow or the institution that set it up might have a webpage listing it, search it. I have left the port and security connection as default.
8. If the information is correct it should work, and when you send an email for a new composition there is a list of addresses you can choose from, the default and the new one. When the new one is chosen the previous/default is not visible.

Google help here for question 3 and 4.

Short answer

Instead of using POP use email forwarding from your other account to be able to use Filters and Canned Responses in Gmail

Explaination

it can't seem to do auto-replies

I beg to differ.

Make sure Canned Responses is activated:

Then you create a filter for emails that are sent to your old email address:

to:(my.old.address@example.com)

EDIT: Note that this will not work for mails fetched through POP3, only for forwarded messages. If your old account has an auto-forwarding feature, that's the way to go. (The other answer here pointed this out.)

You call the filter, say, Old. Then you select a canned response for that filter. Actually, you don't even need to do that. You can autorespond to these emails just the same just by creating a filter for them.

Look at this screenshot: