Can someone please help me with online memberships to Playstation and Nintendo

Splatoon randomly picks your co-players for each session, too. So there's no continuity, further preventing communication.

Splatoon doesn't care about 'friend' status for other players, anyone else with the game can play with you because other players have no form of communication so there's no potential for anything untoward. No chat, no gestures, no grooming, no sending of pics... it's all safe.

Nintendo err massively towards protecting kids in their games, and to be honest online play-with-friends sometimes is less good due to it (eg even if DS is playing Splatoon with friends, they still can't communicate in the game! They have to use a phone app or whatever if they want to talk to each other) but their heart and practice is in the right place.

Sorry, to clarify since I'm not sure that did: There are 7 other players in the game, total two teams of four. The other players are random other people from the Internet and are not necessarily on the friends list, but because there's no mechanism for communication there's no possibility of anything dubious happening. Worst that can happen is that another team gangs up on your DS, but because they can't communicate with each other either that's very unlikely.

In Splatoon the other players are not interactable with, except by running around nearby and covering each other with ink (it's like a shooty game except you cover the ground/other players with ink, most ink wins). There's no way to talk or text, can't even do stupid dances at each other.

Splatoon 2 - No, makes no matter. Nintendo have made it a game that works absolutely fine playing with randoms, and is safe to do so. Friends can team up, so if he persuades his friends to get copies they can do it.

It’s risky yes, so I use my card to pay the membership, then remove the card details after so they are not saved on the device for future use

This is a bit of a hassle, but these systems are deliberately set up to facilitate kids using patents’ cards (as ££££ easily spent. My surprise bill was £800, that’s how I learned!)

Anyone can send a friend request; you can set up Parental Controls so that they can only be accepted via the parent PIN.
"Friend Registration – Restricts users from adding friends via the friend list. It is possible to view activity of currently registered friends – for example, you can see if they are online and which game they are currently playing – but it is not possible to register new friends without the parental PIN code."

The parental controls are slightly weird but effective - they're not on the switch, they're on a phone app. www.nintendo.co.uk/Nintendo-Switch-Family/Nintendo-Switch-Parental-Controls/Nintendo-Switch-Parental-Controls-1183145.html

Good writeup here - www.childnet.com/blog/parental-controls-on-the-nintendo-switch

Splatoon 2 is primarily online, so you basically have to! There is a single player adventure but it's really just training for the online. Pretty good though.

Mario Kart, Minecraft and Luigi's Mansion all have multiplayer online. Not sure about the others.

They're fully legit - they're issued by Nintendo (or Sony, MS, etc). I've been using cdkeys for years, originally they'd email you scans of scratchoff cards! I think they need you to show some ID when you set up the account to help avoid being moneylaunderers.

There are many code shops that aren't. g2a.com are a money-laundering fence, and anyone offering "free" codes in return for taking a survey etc are worse than dodgy. Run away.

Yes, it does need his friends to have Nintendo Online membership and matching games to play. The only games I've ever used online are Animal Crossing, Splatoon and Tetris 99.

For your £13/year you get a few things (I'm not shilling for Nintendo, honest!) - a whole library of ancient NES and SNES games, the online game Tetris99, access to cheap(ish!) "two games for £84" vouchers for certain eshop games, and Nintendo backup for your save games to their servers in case your Switch breaks. That last is the main reason I bought it!

I bang on about the vouchers over in www.mumsnet.com/Talk/_chat/3936734-Anyone-got-a-Nintendo-switch so won't repeat here :D

just so I have this right, if I added his friends and family to his account he would still require an online membership to play with them?

Yes, unless they're physically in the same room and then you can play local play. But if they're at home etc then it would need an online membership.

Yes, you can remove payment methods for PSN and Nintendo. Nintendo you can hide payments behind a parental authorisation PIN code too, don't think you can on PSN.

Best if you never add a payment method and always use top-up cards or voucher codes always, to be honest.

Speaking of which, Nintendo Online code for just £13/year rather than the normal £18 at www.cdkeys.com/nintendo/switch/nintendo-switch-online-12-month-365-day-membership-switch-cd-key just now. They also sell top-up cards at below face value for PSN, and at-price for Nintendo eShop.

Yes, you can do that on the Switch too - charge up the Nintendo eShop account with money or points, but don't add a card on it.

(For everyone other than Nintendo you can get better value on these by buying top-up cards at cheaper than the face value from places like cdkeys.com)

I have known various people get seriously badly stung through synching their own bank card to playstation/xbox. Not that their child does so maliciously, just carelessly.

I have a separate pre-paid card for DS's XBox. They're quite easy to set up online (there's a variety of them available). That way, if he tries to spend money that isn't there, the transaction just gets rejected. (DS's best mate, who is a lovely lad, from a family who do exercise a lot of scrutiny over his internet/games usage, still managed to run up a several hundred pound bill for them because he didn't realise it was real money he was spending - these things happen unless you lock the system down in some way such that it can't).

just so I have this right, if I added his friends and family to his account he would still require an online membership to play with them?

PS4? Yes, both he and they would. "Friend"ing someone just makes them easier to locate in a list when you want to group up online, it doesn't confer any other benefits.

On a Switch, only "Friend" groups are allowed to set up teams etc, so it's more tightly locked down than PSN.

For Plants vs Zombies, you need a second Playstation controller of course, and to set up a second account on the console.

In the game:
"To enable splitscreen, the first player must find the splitscreen console located within the Plants or Zombies home base in the Backyard Battleground. Once the player interacts with the console, there will be an onscreen prompt asking the other player to press a button on his/her controller to join."

The Lego games (basically all of them except Lego City Undercover which is a one-player story game) are all excellent with two local players.

There are many games that support "couch co-op" as it's known, not everything's over the Internet now. Here's a useful resource: co-optim.us/1fOPuF8 (should show you PS4 games with 2+ players locally)