Hydrofoil and other changes to boat are not likely to make much difference. Not with a lightweight aluminum boat. Motor height on transom may make some difference on top speed, but very little on out-of-the hole, unless it's too high and the prop is caveating. Rope length won't matter for getting up per se, but longer may be better for letting the boat do the maneuvers described above without impacting the skier much. Trim may make a very slight difference. All the way down is typically optimal for getting up. If the nose of the boat rises a lot on take-off, then moving weigh forward, such as the helm may make some difference.
A prop with less pitch can make a fair amount of difference, but that depends a lot on how the motor is currently prop'ed and what RPMs it's turning. You don't need a stainless steel prop. A good condition used aluminum prop with one step less pitch may make a significant difference if the motor isn't already turning high RPM. For example if you current prop is a 15" pitch, a 13" pitch may help. Pitch typically changes in 2" increments on boat props.
Motor rebuild could help if the motor isn't running well currently. But instead of rebuilding that motor, look around for something like a 50hp outboard that needs work. I have a friend that goes to lots of auctions. He's picked up many old boats with 50ish HP engines for a few hundred dollars that needed a little work. Often, he'd but the whole boat to get the motor, fix up the boat itself a little and re-sale that for a profit.
Skier technique will make the biggest difference. If there any chance someone with more HP can pull you to re-learn how to get up, then you'd have a much better chance of getting up behind your boat.
If you're having any trouble keeping the skis together, tie a cord between the skis right in front of the boots so the skis can't spread apart more than 4-6 inches. The cord has very little effect once you're up, but will make you much more stable on the get-up.