You have valid concerns and don't be at all worried to voice them - it's good to think about and to feel as comfortable as possible with the process before going forwards. You don't sound at all unsuitable to adopt.
Chemistry/connection is IMHO, very real, BUT not at all necessary for an adoption to be successful. I felt a connection with my eldest just from her paper short profile and photo, and it was real and strong. It's not love or a bond, it's different. I felt that connection to a lesser degree with my middle child and youngest child. One of my friends is a foster carer and she also experiences this with her foster children - some she very quickly feels a strong connection for, and other's she just doesn't. Some she attaches to quickly, others it's harder to feel close to them. It isn't about behaviour, it's something else. The connection I felt for them really helped me feel I should move forward, however many adoptive parents with very happy adoptions never felt that.
When you are linked and then matched with a child, the first stage would be paper profile and probably a photo with that. You need to be okay with what's on the paper before proceeding further.
Different LA's then do it differently. Many will show you a DVD of your potential match before you fully commit, and i guess that's what you'd be looking at seeing in your case, and I think completely OK to ask to see before proceeding. A couple of them will sometimes do something where you observe the child from a slight distance without the child knowing you are there, but that is rare.
Once it is official and you are formally matched by a panel, you make a book and/or DVD of yourselves for your child and they are told you are mummy and daddy who are going to take them home and be there forever, and you begin your introductions period with them. Now in my mind, at this point disruption is the total last resort if the situation is untenable, because at this point the child knows. I don't say this lightly because I have been quite close to disruption myself with my eldest, and my eldest had a disrupted adoption before I adopted her. That disruption had a major impact on her. If you disrupt after being introduced to your child as mummy, it will have a big and pretty negative impact on them, and make it harder for any subsequent adoptive parents, and the child won't trust them not to disrupt as well, like the last ones. Personally, I would never disrupt introductions purely because I was not feeling a connection to the child - I would need to seriously feel that adoption was really unlikely to succeed before I talked ending intros.
Connection means a lot to some adoptive parents, but you know, a lack of instant conection does NOT mean you won't love them. It may make the bonding process harder, but you end up in the same place - mother's love. Lots of adoptive parents feel nothing and go in and are very happy and adore their children. Attachment and love is something that grows over time. In fact my biggest advice to prospective parents is not to expect it to be easy to love and attach, because this is a stranger moving in, and not to beat yourself up over that. If you fake love with a child you aren't feeling anything for, it will come for real in time :)