Right. We've been to Pine Cliffs about half a dozen times, at various times of the year (we own a golf suite timeshare, although we're planning to sell it) so hopefully I can help - apologies if I ramble on but I do love the place and think it's a fab place for families.
First of all, one of the pools is heated, although not excessively - the one by the golf club house, which also has a small kids paddling pool next to it. In my experience the sea's usually cold, as it's the Atlantic - we haven't been in the summer hols though and I am a bit of a wuss...
The Beach Club should be open for the Easter Hols - ie. there'll be sunbeds and shades, towels, and the Beach restaurant. There won't be water sports on offer I wouldn't think, although you can always ring or email and ask. The Kids Club will also be open - the Porto Pirata. You can access the play facilities with your kids or book them in on their own into a supervised session - although the rates are quite pricey.. The kids club area has a race track with scooters etc, swings and slides, a sand area, crazy golf (at extra cost) and there used to be a bouncy castle, although not for the past year or so. There are some pictures of what there is here, along with links to the official sites, and if you'd like pics of anything in particular let me know, I've probably got them stashed away somewhere!
Restaurant-wise, everything'll be open I'd imagine- there are some nice restaurants just outside the gates, as another poster has mentioned. Inside the resort you'll pay 5* prices but again it should all be open.
It can get busy in the main buffet restaurant during school hols so beware - that's the beauty of the golf suites, having a full kitchen, even if it's just to unpack a chinese takewaway (which is fab and close by, and they even give you a free beer or port while you're waiting!) A good place to book is Supertravel Golf - they have access to the golf suites (sleep 4/6) as well as the hotel, and have good rates, although you do have to phone them, they don't have online prices. Again, let me know if you'd like to see pics of the suites etc - they really are a home from home, albeit a little bit nineties decor..
The bonus for us over somewhere like Cyprus is the frequency of flights and the short flight time, and also the fact that DH can play 9 holes of golf in just under 2 hrs door to door, as the suites overlook the golf course. There's plenty of shade from the sun in the pine trees on top of the cliff (hence the name..). The weather should be good, although can't be guaranteed obviously - there is a huge indoor pool and games room if you get the odd period of rain.
Finally (phew!) I think Vila Vita is quite isolated, whereas you can get to Albufeira and Vilamoura quite easily from Pine Cliffs.
Let me know if you need any more info - I'm sure you'll have a good time if you decide to go. Hope this helps!