Hilleberg (and Helsport) are about the best money can buy, particularly for rougher conditions. You are not paying for the name, but for real quality. They are lightweight, but not the very lightest. Their advantage is that they are ultra reliable and will last. If weight is more important than ultimate reliability, various Terra Nova tents are a better bet, or the MSR Hubba HP series. Another very light tent is the Vaude Power Lizard.
Those who hang around here a bit longer know that I like my stuff to be very light and compact, so that I don't need front panniers in most conditions. However, a very cramped solo tent would not be my thing, unless in nice weather. So for me if there is a real chance that the weather will be bad for more than a day, the minimum would be something like the Helsport Ringstind 2 light or the Hilleberg Nallo 2.
As for mattresses I think the Exped Synmat Basic is the best compromise between packed volume, weight, comfort and warmth. It happens to be quite cheap as well. If you will only camp in summer weather (above something like 5 degrees), the Thermarest Neoair is even lighter and more compact, but not as warm. If you want to camp at seriously low temperatures (more than a few degrees below) I would go for the normal Exped Synmat or even the Downmat.
In the UK PHD makes the best bags. They are very light and compact, but also a bit narrow (but you can ask them to make a wider one at little or no extra cost). For camping down to about freezing their Minimus 300 is probably best, with a Dryshell outer. This is not a model they do normally, but they usually have it at a reduced price in their Spring and autumn sales, at a pretty competitive price. Obviously if you intend to camp in colder weather than this, you need a heavier bag, like a Minimus 400 or a Hispar. Together a Synmat Basic and a Minimus 300 will only weigh something like 1300 grams, and pack very small. A down vest would be a very light and compact way to add extra warmth to your bag if and when you need it. And in the evenings you can wear it around the tent. A Synmat Basic, a Minimus 300 and a down vest will keep you warm down to a couple of degrees below freezing, which I guess is all you will ever experience when cycling (unless perhaps at Alpine altitudes).
Willem