Well, Grass Types don't really cover up the Ele weakness as its just a neutral hit and they do not resist it but they are at least not weak to it and some of them are bulky enough to deal with electric type attacks fairy well, but if your looking for a grass type, depending on what you want of course there are a few options, If you want spore support and general status support then Amoongus it also has Clear Smog to get phaze set up sweepers and it has synthesis which is a nice recovery move not to mention its awesome ability of regenerator which means it can switch out and recover health so it can have more longevity and take more hits it also can adsorb T-Spikes and has a nice poison stab for fairys and resists fairy type moves, if you want a bulky wall, bulky nasty plotter , Calm Minder, Phazer kind of pokemon then i would suggest Celebi who has alot of utility, it can force switch out with perish song to stop set up sweepers, It receives calm mind if you want to make yourself more bulky and hit a little harder It gets nasty plot if you want to go on the offensive, And it has a nifty ability of Natural Cure which means you can switch it in to any status move and you can be rid of it just by switching out, Also it has a reliable form of recovery in the move Recover and it is not that bad of a setter of Stealth Rocks or user of T-Wave, it can also be a bulky baton passer i you want to go down there route, Pretty much it has many very helpful uses that make it a great option. Now for Roserade, if your looking for a spike setter or a fast hard hitting mon on the special side with the ability to use synthesis to recover health then Roserade is a pretty decent option, it also receives natural cure which is a really nice ability and makes it a nice status absorber, also it is viable to even put the move rest on Roserade because it will awaken on the switch out thanks to natrual cure and you will be back to 100% and like Amoongus it has that nice poison stab and ability to absorb T-Spikes as well and it does resist fairy type moves, However with Roserade she tends to lack the bulk the other two have but she does have the ability to be the hardest hitting of the three but all three are very help and viable depending on what your need is. however if your worried about a Ele weakness then packing a electric type or ground type deals with them more effectively something like Volt Absorb Jolteon or Lightning Rod Manetric, i noticed you already had Nido who is immune to electric type attacks all together and a pretty nice T-Spikes absorber, but from personal experience a Sp.Def Celebi generally takes electric attacks like t-bolt fairly well and can recover the damage off, but i see the grass type being a nice option to deal with water types and ground types and help take grass type attacks that will be coming towards your Vappy and such, but yea those are just some options that popped up into my head, it really depends on what you want to do and what you want to accomplish. But anyhow thank you for your time.=p