Good to see your sticking your toes in the water and good luck with the boat.
As to your questions i will try to answer them and point you and Roger in the right direction.
1 Insurance, which you will need to get a launch permit that's apart from the obvious reasons for insurance, here is a link to the company which is the most popular in small boating circles http://www.porthcawl-insurance.co.uk/
they are probably the cheapest but someone could prove me wrong.
2 Registration, being a member of the club you can get free launching within Conwy but you will have to pay for your registration i think it's 20 pound but this registration fee covers Anglesea, Gwynedd and Conwy, you will have to pay for your launch at Moelfre so if you are going to be frequent visitors it will be worth looking at the annual permit, not sure of the cost for the year Sam.
3 Service cost's for outboard, can't help you here Sam but there is a boat section meeting at the clubhouse this Friday at 20-00hrs, there may be someone there who could advise you as to the best place to get the engine serviced, a couple of pints and some good general advise, worth thinking about.
4 Anchor, my choice would be a 5kg bruce anchor with 8mm chain the length of your boat, attach the chain to the nose of the anchor via a galvanised shackle then run the chain up the shaft and secure with a plastic tie or some 50 or 60 lb line then if the anchor gets stuck in foul ground you have a decent chance of retrieving by breaking the weak link and pulling the anchor from the nose, carry a spare, you could use a grapnel type for fishing in rough ground, carry enough rope for the area and depth you will be fishing in, an aproximate rule of thumb is x 3 of the depth so if you are in 60ft = 180ft of rope, pays to carry some spare though.
5 Fuel, the older Mercs were a bit on the thirsty side compared to the new generation of 4 strokes but a lot of factors should be taken into consideration eg sea state, how hard you push the boat etc, it would be good practice to carry a spare tank of fuel ( no petrol stations out there Sam and you cant get out and push ). i would imagine the boat will be pretty quick with 50 horses pushing it so take it steady at first until you get a feel of the boat and how she behave's.
6 Equipment, A VHF radio is a must have to be honest Sam as is good quality life jackets and if your purse can strech to it a chart plotter gives you a picture of the area you are in and can id any hazards etc, also great for storing your fishing marks, if a mist comes down it will get you back home, admiralty charts are always good for planning your day, fishfinder is a must too, you need to know how much water you have under the hull.
A secondry means of propulsion, if you intend on fishing alone (without the company of other boats) it's probably even more important to have an auxillery engine 4hp or above, even a set of oars is better than nothing.
Basic first aid kit, fire extiguisher, warm clothing and waterproofs, let someone know were you are going and when are expected to return, be carefull launching of the beach iv'e seen so many losing their vehicles and boats getting bogged down on a flooding tide, Hope i haven't put you and Roger off by bringing up some of the pitfall's Sam on a positive note on a lovely summer's day there is no better place to be, there's probably 101 things i have not mentioned, enjoy and stay safe.
ps if you were thinking of doing the RYA level 2 boat handling course i can only recommend it, a great course you will learn a lot and it's a fun couple of days.