Yes definitely fine to freeze. DS1 loved apples so I always combined with less favorite foods, like chicken. It was binding for him though so I had to back off sometimes if he was heading in the constipation direction.
I love my Beaba! It both steams and cooks, so less to clean afterwards.
As far as trays, I found this on Amazon and its perfect! They have silicone bottoms that allow you to pop it out easily while providing a lid and not taking too much room in the freezer.
Turning brown with air contact is just what avocado does as it oxidizes; it doesn't mean it's bad, just unappealing-looking. If it bothers you, though, the only real option is to only feed avocado fresh, because it will always do that unless you use additives.
I bought the sage spoonful system, DD has been eating solids for just over 2 weeks now & im loving it, also customer service is awesome and really responsive when u mommy brain out and boil sanitize the wrong piece... It didn't come with many jars so I bought regular 4oz. Jelly jars and freezer lids for them, I take them out of the freezer the night before I need them and they fit perfectly in my bottle warmer so I just use that to warm them up for meals... So far so good, LO LOVES butternut squash
Re: Making/Storing Baby Food
As far as trays, I found this on Amazon and its perfect! They have silicone bottoms that allow you to pop it out easily while providing a lid and not taking too much room in the freezer.