Before you start

I have been working on a project to convert a a fairly large website for a non-profit from being a large collection of individual .html pages to a data-driven site.

Sorry for that vague subject line, but I manage half a dozen websites.

I am looking at Drupal, and I need some clarification for some of the pre-install post already made.

OVERALL GOAL:
Combine 3 sites (1 blog and 2 forums) user database through a 4th main website.

software:
Forums are IPB 1.3
Blog is WordPress

backbone:
apache
mysql

Can Drupal 4.6 work with php4?
Forgive me if this sounds stupid, but I'm only ten minutes familiar with drupal.
Server has php4

I need to build a very simple web site. We're talking 6-10 pages of content and a few photo galleries.

Requirements

I've been given a set of requirements by my client and I've figured that modifying Drupal would be my best bet. What I would like to check is whether the following requirements are feasible to achieve. I know XHTML, CSS, PHP & MySQL, so I'm capable of making the mods if Drupal is flexible enough.

Requirements
Web Page Customisation - would I be able to create my own design using XHTML & CSS to be used in Drupal?

Can I install Drupal with PHPMyAdmin? I am also reading INSTALL.txt and I wondering if there is something else that makes it easier for someone like myself that never messed around with MYSQL and knows very little about PHP? I am trying to make a site that is part website, with categories and a blog. So is this possible with Drupal?