Just seen this Liz and as we went in March a few years back I thought I would respond.

1) Yes, certainly more than we had in November. Happy hours until 8pm in many bars in the Old Town, plenty charging €2 a pint and lots of specials at restaurants. In my opinion you can eat for as little or as expensive as you want in Albufeira. Our trips to Albufeira have tended to be second holidays (and we are very grateful) so budget has been on the lower side and we have eaten accordingly.

2) Mixed I would say. When we went in March it was grey and overcast and not particularly warm. The sun did get out a few times but nothing is guaranteed at this time of year. In contrast November was sunny with blue skies and kicking around 18c which was nice.

3) Nope. This has been exaggerated to death on TA and other forums. We went in November last and if I believed everything I read, we were heading into one of the most dangerous areas in the world. Be aware of your surroundings as you would anywhere in the world. We walked from Brisa Sol to the Old Town, Strip, Sta. Eulalia day and night and didn't have a problem. March should be busier even still with a few more tourists than we had in November.

4) Not sure but still plenty of options all over Albufeira. I went to Kalamaki in Zakynthos in 2010 and there were lots of empty shells where restaurant and bars has fallen on hard times. I didn't see as much of this in Albufeira, if at all in some places.
Enjoy your holiday!