The Yam is a danforth style anchor. "Reasonable" holding on most substrates.
The grappy is crappy on mud or soft sand as the tines (spikey bits) don't get enough friction.
Mushrooms are in theory OK for mud & sand (never used one, not sure I've even seen one in the flesh). But in theory pants on rock /kelp where they can't dig in.
Bruce has the advantage of not having those spikey side bits the danforth has and no folding bits to seize. But lack of folding makes it difficult (or at least harder) to stow.
6.5lb is not hugely heavy. But may be OK for hook and stay aboard, just be conscious where you are dropping the hook and where you'll drift to if you unhook by accident... If you have GPS use the anchor alarm on a tight circle.
Not seen vinyl coated ones available elsewhere. Would be curious how well the coating survive a few rocky anchorages...
Rope looks a bit skinny - do others agree?
That snap clip is to attach the 'bitter' end to the boat so that when you throw the anchor out you don't loose the whole lot. DO NOT use it to join rope to chain. ensure once the anchor is deployed the inboard end is cleated securely as I wouldn't trust the snap clip under force.
Chain length is short. May not be a major issue if you are using anchor in sheltered locations etc with a sandy bottom where the rope wont get worn by the rocks and a few attempts at setting are available if it doesn't lie right on first try. BUT REMEMBER your anchor is your handbrake and you might need it in rough and dangerous conditions...
I suspect the best anchor for your use might be the plastic cooper anchor... Home — Cooper Anchors UK — The World's Best Anchor
I gather they have a bigger size coming 'soon' which might be even better...