12-day Portugal tour--breakfasts? Any advice?

I've always been impressed with the breakfasts on RS tours. We've done 14 tours (but not this one,) staying in probably 40 - 50 (?) hotels, and only one has ever disappointed us with the proffered breakfast.

Usually there are cold cuts, cheeses, yogurt, breads, sweet rolls or cakes, fresh fruit. Often there are cereals, occasionally eggs. Always coffee, usually juice - sometimes freshly squeezed. I don't eat sweets, so I always look for unsweetened plain yogurt, and usually it's there. One hotel we stayed at on the Eastern France tour had homemade yogurt!

Hotel breakfasts are one of my favorite things about traveling in Europe.

I haven’t been on the RS tour but have stayed at the Hotel Lisboa Plaza, one of the hotels the tour uses in Lisbon. The breakfast buffet was extensive and included plain yogurt, fresh fruit, muesli, cheeses and cold cuts. You make your own coffee with the Nespresso pods of your choice, which includes decaf. All of the hotels i’ve Stayed at in Portugal and Spain have had similar offerings.

Jeans and leggings are fine. Your capris are probably fine as well.

I did the Portugal tour this past April 2019. Jeans, leggings, and even travel capris will be appropriate dress -- I don't think any are too casual for Portugal.

I always carry-on with my 19" suitcase so rely on RS tours to take us through at least one city with either (affordable) hotel laundry or laundromat options, but the Portugal tour had fewer options than most of the other RS tours I've taken. Our guide even acknowledged this. However, I did find a clean laundromat to do my laundry in Coimbra, at the top of a hill with a lovely view and good prices. Google "Varanda de Sta. Clara - Lavandaria Self-Service - Coimbra" in Google maps. Note that there are only 3 washers and 3 driers.

We took this wonderful tour 3 years ago and stayed at Hotel Lisboa Plaza. As mentioned up thread, the buffet breakfast was extensive. I don't recall oatmeal (my favorite) but was happy with all the offerings along the journey. We visited in September and it was unusually warm. That said, October should be lovely. Lightweight jeans, lightweight leggings and capris are perfect. Saúde!

You’ll have plenty to eat on this tour, but try and broaden your horizons. While I avoid sweets on a day today basis, the pastries in Portugal were a real surprise. We usually had fruit, yogurt, coffee and a shared pastry for breakfast. With all the walking we gained no weight. I do not recall seeing oatmeal.

You will eat very well on this tour, breakfasts have a lovely spread. We took this tour in 2014 and I know several hotels have changed but you’ll have plenty to pick from at breakfast every day.

We just returned the middle of September from this tour. With the one exception of one "adequate" breakfast buffet, the breakfast buffets were very extensive and excellent. Lots of exceptional fresh fruit, yogurt, local breads and pastries, typically scrambled, but sometimes hard boiled eggs, bacon, "sausages", cold cuts, a wide variety of cheeses, usually a few cereals, but I do not recall any oatmeal. While I am a tea drinker and we are from Seattle where coffee is king, and with the exception of one of our fellow travelers who typical dashed out for a local espresso, the coffee seemed fine with some locations offering a variety of coffee style options.
While a male, I travel with a very fashion conscious partner and we both noted that dress even in Lisbon and Porto is very casual.
Perhaps the weather will be too cool during your trip, but I would suggest bringing swim wear as a couple of our stays had terrific pools.
We spent an extra day at Porto before moving on to Spain.
If you are arriving a day or two early and want to visit Sintra which I would highly recommend, take an early train before the tour starts as there was no time to go once the tour starts.