Should I not bother with these workbench features as they might not be suited for softwood?
I was going to suggest in a Comment that a complete list of the features you might like to add would be useful, for replies to be as comprehensive as possible by going through them as a checklist. But actually I couldn't think of any feature that would be precluded because the top is made from softwood. In particular since you're planning a laminated top it will be very very strong and should be more stable than if made from a solid board as was the norm back in the day.
Example being I can see a holdfast wearing out a dog hole fairly quickly if used regularly.
That shouldn't be a worry. There are numerous benches out there now that have solid MDF tops and we can extrapolate usefully from those, since MDF is significantly softer and more friable than pine at the edges. Some of these benches use holdfasts of one type or another apparently without a problem. If I remember correctly what does tend make dog holes wear excessively when used with a holdfast is if they are drilled a little too large. The other major issue is if the top is too thin to properly support the locked holdfast, but that won't be a problem for you.
Now likely I will not be going to crazy and will just make a leg vise with a plain flat top. I am considering just using pine for that as well as it is available to me.
Coincidentally I happened to post a pic in the six-pack of images for this Answerthis Answer a short while ago that shows a leg vice with softwood chops (faced with leather it looks like), so that's a clear example of it being used. And there are numerous other vices posted online with chops or jaws made from pine/fir/spruce.
Just as an aside, there is wide disagreement in woodworking circles about the ideal material to make vice jaws from.
On the one hand there's hardwood or hardwood ply, cited for strength, stiffness and durability, on the other hand others prefer to use pine or MDF specifically because they're softer — far less tendency to crush or bruise softwood or MDF project pieces.
So up to a point the woods you most commonly work in can drive the choice. If you rarely if ever work in hardwoods it could be useful to have vice jaws made from softwood (laminated for stiffness if necessary). It should be mentioned though that some woodworkers who build vices using hardwoods get around the problem (to some degree) by lining their vice jaws with leather, suede, rubber or cork. In addition to the cushioning effect these all give improved slip-resistance as well, so it's something worth considering regardless of what the vice is made from.