Paving paint would be a cheaper option, Modwood is expensive but there is no maintenance, you could you use just ordinary timber decking for a timber look as well but it won't be as inexpensive as paint obviously. I think paint will look cheap. If it was me and I only had a choice between painting the tiles or leaving them as is, I'd leave them as is. I'd worry that it would scratch off the tiles especially on the ends. I used to have a garage painted in grey paving paint, it was very Matt looking, not shiny and the grey looked really grubby after a while. The tiles may not be your favourite part of the porch but make the decorating items the feature or save up and get them replaced with a grey tile you love. It's a small area so it shouldn't cost the earth. Do the removal yourself which would save you some money. It would really update the front of your house.

I agree about the idea of putting roller blinds on your door , matching the colours of the others must mention about Annie Sloan paint : it is a chalk paint and you can apply it on any wood surface with at having to use primer, what " seals" the pain is the Annie Sloan wax you apply afterwards. You can Buy Annie Sloan on line , i use Annie Sloan a lot.it is expensive if you want the legs painted black to be smooth, just paint and wax , but one coat of Annie Sloan does not give a good coverage. It you want it " distressed" slightly, then just sand a few it on the edges afterwards, before the waxing With a slight " distressed" leg look, but you would need to give the top of the table a light sanding to " rough it up" on the edges if you want a good solid, coverage, Annie Sloan is not the right choice have a look on eBay, I have just bought some cages light to fit near my table outside ( I was just playing around with them yesterday before the electrician comes toda), they were only like $46 each

everything you've suggested sounds ideal and you will only need to build a frame underneath the stairs to create a wall to the side of the steps and directly under the top step to allow for a door and cover with the same wall lining and either add an electric or battery operated light under the stairs and shelving to suit what you want to store

once the groundcovers are well established they can be raked over with a flexible rake and quickly recover and some of the fallen leaves will help with mulch..i guess the challenge is to prepare the site well and make sure that the new groundcovers are planted late say in Autumn with plenty of time to be well established before next autumn but i think that nothing looks better than a carpet of Autumn leaves with some crocus bulbs poking through and i was never in a hurry to rake all the leaves up at once